Nadia, a brunette in her early thirties, is clearing tables in a busy diner when a young woman calls for her. "Excuse me, waitress?" Nadia looks over to the woman and smiles, "I'm afraid the teriyaki chicken is no longer on the menu." The woman and her husband look at her, confused. Nadia explains that's what the woman ordered the last time she was in the restaurant, but the couple insist they've never been there before. Nadia looks at the wife. "Your hair was lighter . . . you had on little round glasses." The husband is interested, but not too concerned. "Sounds like you!" he tells his wife. But she plays it off and tells him Nadia is just going for a bigger tip. But she's not. Nadia remembers it perfectly. "It was last August. Saturday, the 14th. You were wearing a blue dress with polka dots. Your eyes were puffy, like you'd been crying," she tells the wife, definitively.
Her husband puts the pieces together and realizes that his wife must have been with her old boyfriend that day. Nadia tries to back away from the carnage. "I'll go get your water." But as she walks away her legs buckle and she falls flat on her face, cutting her legs on broken plates and glass. Diner patrons help turn her over, but she's shaking and crying. "I can't move my legs!"
House has convened the team in a darkened radiology room to tell a story, shining a flashlight on his face for maximum eerie effect. "Drama. Picture a door, unlocked, with the key of the mind. Two medical cases, both more fascinating than the last . . ." Masters interrupts to tell him that makes no logical sense and gets an eyeball full of flashlight beam. "This is not a door to logical sense. Also, shut up. Case Number 1: Thirty-three-year-old woman, named . . . something I can't remember. You'll see the irony in a second. Presenting with temporary paralysis, high CK levels . . . and a perfect memory." That gets everyone's attention, as House turns up the lights so they can read Nadia's case file. Chase wonders how perfect her memory really is. "Perfectly perfect," House says. "Hyperthymesia: complete recall of every moment of every day since puberty."
House touts the cool factor of Nadia's condition, telling them she's one of only a handful of recorded cases. Masters reads from the file that she was able to tell the emergency room doctors the exact starting and ending dates of her last eight colds, but Foreman is less impressed. "So we have two symptoms: temporary leg paralysis and elevated CK." "Well, obviously you're not suffering from the same condition, because you've already forgotten my dramatic voice-over," House reminds him.
But Foreman insists her memory is unrelated. It's been twenty years since the onset of the hyperthymesia; plus, he isn't aware of diseases that cause great memory, just ones that destroy it. "MRI showed no evidence of stroke or a tumor, so probably a toxin," he concludes. Picking up on this, Taub sees that Nadia's a waitress and says they're no strangers to botulism or alcoholism. He wants to search her diner and where she lives. "Or," House says, "we could search the brain. You know, where her memory lives. Save the gas."
He assigns Taub and Foreman to search the home and Chase and Masters to get a complete patient history. Taub reminds him that he mentioned two cases. "Oh, yeah, thanks," House says, as he lights up an x-ray screen to show not an x-ray but one of the hospital's promotional posters featuring Taub. "The case of the forty-five-year-old doctor who failed his pathology recertification exam, who's going to lose his board certification and get fired."
Taub says he was sick when he took the test, but he's retaking it in a week. Since Cuddy is upset that the hospital's literal poster boy could be fired, House wants the team to help Taub pass the test. He decides that Taub should have a tutor. "Choose your poison: Chase, if you prefer pounding Aussie beers and commiserating over the suckiness of divorce; Masters, if you want nervous energy, flash cards, and obnoxious pieces of arcane trivia; Foreman, if you need to be berated by a humorless hard-ass." Taub chooses Foreman, which House takes to mean he must really be worried about passing the test.
House finds Wilson in an exam room with an elderly woman patient. "Need a consult, Dr. Wilson." Wilson wraps up with the patient, who thanks him and says, "Be sure to give Sarah a kiss for me." Wilson explains it away to House as an early symptom of dementia. Back to the consult: "I need your medical opinion on what bar we're going to hit for happy hour tonight."
House has determined that this is the end of his three-month "pity party" over losing his last girlfriend, Sam. But Wilson says he can't go. "Because of Sarah?" House asks. "Yes," Wilson sighs. "Because of my senile patient's granddaughter. I'm busy!" House is confused and now determined to figure out who Sarah really is.
He finds Cuddy by the nurse's station and asks about Wilson's friend, "Sarah." She barely looks up at him and continues what she's working on. "My computer crashed. Lost my database of his acquaintances." From this, House concludes that both Wilson and Cuddy are lying to him. She looks him right in the eyes: "I know nothing about Wilson having a friend named Sarah. Satisfied?" She walks away, but of course he's not at all satisfied.
Foreman and Taub are searching Nadia's apartment, which is full of jigsaw puzzles, while Foreman annoys Taub with test review questions. "Hey, you picked me," he tells Taub. "You said you wanted a hard-ass." Taub points out that it was House who said that. Taub just wanted someone who'll mind his own business. "I'm totally fine. I aced my first pathology boards," he says.
"Medicine has come a long way in the last hundred years," Foreman answers, while checking under Nadia's kitchen sink. Taub pokes around Nadia's coffee table and tries to casually suggest: "You know, I heard of a guy who knew a guy who could get the exam ahead of time . . ." But he quickly backtracks when Foreman shoots him a disapproving glare. Meanwhile, Foreman's found something that could actually be related to the case: laxatives.
House isn't there when Foreman and Taub get back to the office, so they call him. He's searching Wilson's car in the parking garage. Foreman asks why. "Because I already searched his office." Taub says that they've got an answer to Nadia's condition: magnesium poisoning. Laxative abuse can lead to hypermagnesemia. House is impressed with their "outside the box" thinking, but he's distracted by something he sees in Wilson's trunk: a bag of something that looks an awfully lot like marijuana. He sniffs the bag and then tastes the contents, disappointed.
"Everything OK?" Taub asks. "No," House tells him. "For a second I thought Wilson might have drug problem. Turns out it's much, much worse." Taub doesn't get it, but he barrels on. "So, we push fluids and wait for her kidneys to clear the hypermagnesemia?" "You'll be waiting a long time, since that's not what she has," House says, while he pulls a package of syringes from Wilson's trunk. He says Nadia's BP and respiratory rate are normal. "While you two were being so impressively outside of the box, you missed the actual box." He's done with Wilson's trunk and wants to know if Chase and Masters have completed the patient history.
"Two light beers, November 16th. One really bad glass of Pinot on the 17th. Uh, nothing from the 18th . . ." Nadia is recounting her recent history.
Masters interrupts: "Shouldn't you be working for NASA or something?" Nadia looks at her. "You mean why am I just a waitress?" Masters apologizes. "Remembering something is not the same as understanding it," Nadia tells her. "I'm not a genius. I love my job. I'm great at it. Keeps my mind busy."
House walks in the room as Chase is bandaging Nadia's legs. "Hi. I'm Dr. House, and you are not pooping. The question is: Are you also a klutz?" When Nadia says she guesses she's no clumsier than anyone else, House asks why she has to guess. "You've got a perfect memory. I was told there'd be numbers, dates, fireworks." Nadia gives in: "What do you want to know?" House starts:
"Let's go back to 2008. How many trips, stumbles, and falls did you have?"
"This really works. Cool. How about 2009?"
"Even cooler. Last year?"
House turns to Chase and Masters. "Either of you figure out how we can make money in Vegas off of her?"
Chase notes the spike in discoordination. "If you add the constipation, it's early onset Parkinson's," House says. He orders a full neuro exam and levodopa.
Wilson comes home to find House in his kitchen, with an overturned cardboard box next to him. "Oh, I'm so surprised you broke into my apartment without telling me. What is this?" House tells him it's an intervention, and pulls out all the items he stole from Wilson's car. "Exhibit A: a baggie filled with nepeta cataria . . ." Wilson spots the box on the counter. "That had better not be what I think it is," he tells House. "If you mean your new junkie girlfriend, then yes," House says, as Wilson lifts up the box: it's a big, white long-haired cat. It's Sarah. "OK, fine. I got a cat. Release the Kraken."
House tells him he doesn't realize the severity of the situation. "You are rapidly approaching end-stage male spinsterism." Wilson's pager goes off, but House continues. "That cat - that diabetic cat that you're shooting up with insulin and buying dime bags of catnip for - that means you've given up on ever finding anyone." Wilson tells him he's completely overreacting. "If I'm completely overreacting, then why did you lie to me?" House asks him. "Um, because I knew you would completely overreact," Wilson says.
But House isn't going to let this go. "Its name is Sarah. Cats aren't named that. Women are. What the Freud is that about?" Wilson says she belonged to a neighbor who passed away, and he felt bad. "Sarah would have been destroyed at the shelter," he tells House, as he gives Sarah a shot.
"Who wouldn't want a cat who croaks if you're not at home twice a day to shoot it up?" House says. "It's like having your own button on 'Lost.' You know, I'm pretty sure that there is a river nearby . . ." Wilson tells him to cut it out. "I'm keeping her."
Foreman and Masters are in Nadia's room. Masters is performing a shoulder exercise on Nadia. "So, I have to ask: is there a trick you use? Mnemonics? Meditation?" Nadia assures her there's no trick involved. "I don't even try, really. It's just there. Is my memory going to go away, with the Parkinson's?" she asks Masters. Foreman says it's a possibility, but they still have to run a number of different tests before confirming the diagnosis. Nadia leans back in her bed. "Well, here's hoping for cancer." Foreman and Masters are confused, but just then a woman comes in Nadia's room, carrying flowers. It's Elena, Nadia's older sister. Nadia doesn't seem too excited to see her sister.
"You don't have to be here," she tells Elena. "But I'd like to pretend you'd visit me if I were in the hospital," Elena says. Nadia sees Elena has brought daisies. "They're your favorite," Elena says. Nadia fumes. "They're my least favorite! I was stung in the face six times . . ." But then Nadia starts breathing fast and puts her hand on her heart. Foreman rushes over: "Fast, wide complex rhythm. Get the panels," he tells Masters.
Back in House's office, Chase says that the cardiac involvement rules out Parkinson's. They're back to transient paralysis and high CK, now with arrhythmia. But House has other things on his mind. "Masters, when you finally blossom into a woman, would you ever sleep with a man who had a cat?" When she says yes, House tells her she's wrong. A quick poll of the men to find out who's had a cat (none of them) and who's had sex (all of them), and House tells her, "I think, as your people say, 'quod erat demonstrandum.' "
Chase says an excess of catecholamine could have triggered Nadia's arrhythmia, but Foreman rules out a pheochromocytoma since her blood pressure was fine. Masters says maybe the heart problem is behind Nadia's symptoms. "If it's not pumping effectively, the muscles shut down, CK elevates, coordination suffers . . . Her heart problems started when Nadia saw her sister. Stress-induced arrhythmia could be caused by long QT syndrome."
Taub points out the sister was hardly in the room, but Masters remembers that Nadia said they'd been estranged for over six years. "That's a lot of tension." House agrees and orders a stress test to confirm long QT. Chase says they can't put her on a treadmill, because it'll pull out the stitches in her legs, so the test will have to be drug-induced. "Drugs are never the answer," House tells him. "We want her heart to go crazy. There's something simpler and safer. Use the sister."
House confronts Cuddy in her office about lying to him earlier. "No, I said I didn't know anything about Wilson having a friend named Sarah. Under 'House' rules, that is not a lie," she tells him. Cuddy says that Wilson's lonely and a cat can provide affection. Why is it so important to House?
"After divorce number two," House says, "he fell into a committed relationship with a three-legged Siamese. He stopped answering his phone. Redecorated his place like Grey Gardens. He wasn't able to come back to humanity until a window was left suspiciously - and heroically - open. How that cat opened the window I will never know." Cuddy says he just needs more time. "Leave him and the cat alone." "I won't if you will!" House says as he walks out of her door.
Nadia and Elena are in the imaging room. Elena apologies for the daisies. "I always get it confused if you love or hate them." Nadia offers to tell her exactly how many times she's told her she hates them. "I didn't do it on purpose," Elena says. In the control booth, Chase and Masters see that Nadia's heart rate isn't moving. "The sister stress pot needs stirring," Chase says, looking at Masters. But Masters doesn't want to start a fight between them. "Just agitate a little. Use something from the history. You're not lying to them. In fact, you'd be telling the truth and serving their medical needs," he says.
She's not convinced, but she agrees and walks out toward the sisters. "You haven't seen each other in a while, huh?" Masters asks, casually. "I heard the story of the time you hit Nadia with the car; it must have been pretty scary," she tells Elena. Elena turns to her sister: "Why would you tell them that?" Nadia says they asked about broken bones. Elena swears she checked her mirror, but Nadia disagrees. "You know that's a lie! You knew I was getting the mail, and you just didn't care enough to check. Just like you didn't care that you ruined my twenty-third birthday!" They both start yelling at each other and soon Nadia's heart is racing. Masters tells Elena to leave the room.
When Taub arrives at his hotel room, there are still moving boxes all around, and so is Foreman, who's been waiting for him. "When are you getting an apartment? Or at least a storage room," he asks Taub. "I'll get to it," Taub says. "I like it here. They have video-on-demand." Foreman has a practice test to give to Taub, but Taub would much rather watch a movie. Foreman reminds him he's only got three days left to study.
"Why is everybody's first assumption I'm going to fail this stupid test?" he asks Foreman, who reminds him that he did fail the test. Taub again says he was recovering from the flu when he took it. "I don't care if you were dying from Ebola, you shouldn't have gotten less than a 70. You're nothing but excuses and distractions." "Well, it's a nice match with your condescension and superiority," Taub says. That did it. Foreman gets up to leave. "Enjoy the movie."
Masters finds Elena waiting on a bench in the hallway outside Nadia's room. She tells Elena that they've started Nadia on a beta-blocker to control her heart rhythm and she should be fine. "Did you hear that she banned me from her room?" Elena asks Masters. "I know I'm not perfect, but she's . . . oh, she can be such a bitch. She never, ever, ever lets anything go. Tell Nadia she doesn't need to worry about seeing me again," Elena says, grabbing her things to leave.
But Masters' conscience gets the better of her: "I started the fight. We needed her heart rate to rise so I provoked you." Elena is furious. "You can't play with people like that." Masters offers to explain what happened to Nadia. "No, it doesn't matter," Elena says. "It's just one more fight for her to remember. Guess you're both bitches," she tells Masters, and then walks away. Masters is near tears when Chase calls her into Nadia's room. "Smell her breath," he tells Masters. She leans in to Nadia. It's ammonia. "What is it?" Nadia asks. "I think your kidneys are shutting down," Masters tells her.
When the team, minus House, gathers again in House's office, Taub says that failing kidneys put the heart back on the list as a symptom. Chase offers amyloidosis, but Masters says they'd have seen stiff heart on the nuclear study. But an autoimmune disorder could account for multiple organ system failure and paralysis. Taub says a number of them would fit, like Guillain-Barre or polymyositis. Meanwhile House has arrived with a handful of papers he's riffling through and stacking in front of Foreman. Foreman suggests MS or polyarteritis nodosa, and Masters thinks it could be SLE, but they're all becoming intrigued by whatever it is that House is doing.
"Why are you giving me these?" Foreman finally asks. "Because," House says, "while they're off running all these tests, you will be submitting the insurance forms." Foreman says they have an entire department for that. "Exactly, the Foreman department, of which, you are the foreman, Foreman. I know you've got the time, because a little wallaby told me that you recently vacated your post as Taub's savior."
Foreman says what Taub needs is Ritalin and a babysitter, not a tutor. But House says if Taub doesn't pass his test, then Foreman will be submitting their insurance paperwork permanently. Taub thinks there's something else going on. "This isn't really about Cuddy, is it? It's about you. You don't want to lose me. Deny all you want, but I think you care," he tells House.
House isn't going for it. "Don't think you can disgust me into pulling Foreman off you," he says, and orders them to pulse the patient with steroids for the autoimmune, and put her on dialysis for the kidneys. "Treat the Taub with insults and small slaps for the obstinacy, and start him on studying for the brain failure."
Wilson is in his kitchen, carrying Sarah under his arm, talking on the phone and retrieving her medicine from the refrigerator at the same time. Just as he's about to hang up he sneezes, then sneezes a couple more times. What's going on?
Later, House is in his office, and he smiles as he hears Wilson sneezing down the hall on his way into see him. "You planted something in my apartment to make me think I'm allergic to Sarah," Wilson accuses House. House leans back in his chair. "Paranoia is the first sign of toxoplasma gondii, the parasite linked to Crazy Cat Lady Disease."
But Wilson knows he's not being paranoid. "I'm allergic to ragweed and dandelion. I'm not allergic to cats! You're trying to gaslight me," he tells House. "And your subconscious is afraid that you're going to die alone, and it just comes out as gibberish and sneezing. Prove that I'm overreacting. Boys night out. Goodtime Charlie's. They just changed their slogan to 'Where the trashiest ladies get trashed,' " House replies.
Of course, Wilson points out the hypocrisy in House's lecture. "Until recently, your lifestyle of choice was self-exile." "But I never had a cat!" House says. He tells Wilson to pick him up at 8:00, and Wilson sneezes out the door.
Chase is in Nadia's room, prepping her for the dialysis. He mentions the fight with Elena. "You think I was too hard on her," Nadia says. Chase tells her everyone has grudges but Nadia disagrees. "It's not a grudge. It's common sense. It's simple math. She's hurt me more than she's helped me. Most people edit their memories. They add small little lies, so they don't have to face the truth. My memories remain the same. My truth never changes, because my truth is the truth." Chase thinks that must be a lonely way to live, if no one ever gets forgiven. But Nadia says she does forgive. "As long as the good things they do outweigh the . . ." and then suddenly she is unable to breathe.
When Taub enters Foreman's apartment, he's surprised by the classy dÃ©cor. "I just always pictured your place with shag carpet. Like, kind of a Mod Squad vibe." But Foreman isn't playing around. "You don't look at or touch anything that doesn't belong to you, including food. You will study, and you will sleep, and you will not leave my sight until the exam." Taub heads for the door, but Foreman says, "This is no longer about your future. It's about mine, too. You fail, and I will kill you."
Chase, Masters, and House are in Nadia's room. "Respiratory distress means we were wrong about autoimmune," Chase says. Masters says that it could be pulmonary edema from the renal failure. But House pulls down Nadia's blanket to look at her legs: she's got hives. Chase wonders if it's an allergic reaction - but how could it be, since they pumped her full of steroids? House thinks he knows, and he reaches for an unopened dialysis tube. He unwraps it and rubs the tube with the solution on Nadia's arm. Hives appear instantly. "I have good news and bad news," he tells Nadia. "The good news is I was right about you having some autoimmune disease. You're just allergic to the dialysis." It doesn't take long for Nadia to get it: "If I can't have the dialysis and my kidneys are failing, won't that mean I'll die?" "Well, you figured out the bad news," House says.
Walking in the hall, Masters asks Chase and House what they should do now. "Look for another case. Even if you're right about autoimmune, we now don't have time to prove it. Transplant board will never give her a kidney." What about a relative? "Which relative?" Chase asks. "The sister who walked away and told you she was never coming back?" Masters feels like even though the sisters were already estranged, they made the situation worse, but Chase says their relationship was beyond repair. "Nadia literally keeps score. She tallies everything. She decided Elena's done more bad things to her than good, and doesn't deserve her affection."
House says she's probably right. "Unlike everybody else in the world, her memory seems to let her keep a pure and objective view of people and relationships. There's no petty emotions or agendas fogging the windshield. Why is that so wrong?" "Because it's making her die alone of kidney failure in room 205?" Masters says.
But House thinks they can still get to the sister. "I'm sure she's got plenty of subjective emotions we can exploit. Why don't you go channel your guilt and see if you can get her to cough up a kidney," he tells Masters. She doesn't want to do it, but House says she's the one who made the mess, so she's got to fix it.
Masters is in Elena's apartment. "I didn't mean to make you hate her," she says. "And, now that her kidneys have failed . . . I've always been a book and equations person. People are problematic and random and messy. And with sisters . . . I mean, I had a cousin, who I was close to, and when our menstrual cycles synced, it was like gladiator school." Somehow, through that, Elena gets what Masters is after. She agrees to give Nadia a kidney. "Really?" Masters asks. "It might not fix your relationship. Uh, I probably shouldn't have said that."
At Foreman's place, Taub has persuaded Foreman to play video games in between studying. Taub admits to Foreman that he didn't really have the flu when he flunked the first test: "I just choked." Foreman doesn't understand; he makes life and death decisions every day under constant pressure, and he doesn't choke. "I got a perfect score on my first pathology boards. I kept thinking whatever my score is now, that's going to be a measure of the distance between me and the man I used to be."
Foreman tells him he's got to quit psyching himself out, but Taub thinks that's going to be hard. "The last test was before I lost my wife and my home, so I'm sure the next one will go much better."
Chase appears at Nadia's door. "We found a donor," he tells her. She doesn't understand - she wasn't going to be on the donor list. "It's your sister," Chase says. "Just thought you should know." And he leaves, with Nadia not saying a word.
The surgery goes smoothly, and soon Nadia is being awakened from an anesthetic haze by Chase. He tells her everything's looking good, but Nadia is shaking her head. "Nadia, come on, open your eyes." Suddenly she starts seizing.
Walking to House's office, Chase tells House and Masters that the seizures mean the steroids aren't working. And Masters says the tests have come back: they were wrong about it being autoimmune. House wants to know if Nadia thanked her sister. Chase says no, or at least not yet. "See if she will," House says. He wants to find out if she's telling the truth. "She claims that she objectively sees reality. Weighing the good and bad in people. If that's true, I don't care how many times her sister borrowed her scrunchy without asking, a free kidney ought to trump all the bad stuff."
Masters wants to know what it means if it doesn't. "Then she sucks like the rest of us." Chase says maybe they should check out her blood. "Clots could hit her leg, heart, kidney, brain . . ." House says that if it's Factor V Leiden, it's the easiest to treat. He wants Nadia started on heparin. "And ask for the thank-you."
Back at Foreman's, Taub agonizes as Foreman grades a practice test: 54 percent. Taub can't believe it. "They make the practice tests harder than the actual exam," Foreman tries to reassure him. "Oh my God, now I'm choking in the living room. This isn't going to work," he tells Foreman. He's going to call his "guy," and buy a copy of the test. Foreman snatches the phone away from him. "I know it's cheating," Taub says. "And I suck as a person. But the test is tomorrow morning."
Foreman tells him there's more at stake now than cheating. "It's about your confidence. You steal that test now, you'll never get it back." Taub says he can't handle failing at anything else in his life, but Foreman insists that he's a good doctor and he knows everything that's on the test. "You just need to know that you know it." Taub is starting to feel better. "We need you on the team," Foreman keeps pumping him up. "So we're going sit here and take another practice test, and we're going to keep taking them until you've kicked its ass! You can do this! You feel me?" Taub gives a not-terribly-confident "Yeah."
Soon after, Taub is meeting his guy in the park, buying the test. Foreman's there, too. "I feel like we just buried a hooker in the desert," Taub says. "There'll definitely be another time to rise up and turn things around," Foreman tells him. "Next time," Taub says.
Chase is changing an IV bag in Nadia's room. She's not feeling any better, but he says it will take time for the clots to resolve. "Your sister's recovering well," he tells her. "If you're really adding up the good and bad . . ." Nadia asks if she can see Elena.
House and Wilson are at the bar, and it's packed with women, many of whom House is tagging as too fat, too thin, too desperate or not desperate enough. "Come on," he tells Wilson. "You can insult them too." Wilson says he'd rather not. "If you objectify them now, you'll feel more comfortable when you tie them to a table in your basement later," House tells him. Wilson agrees to give it a try, and he spots one girl who's "too armpit fatty." Then House spots a beautiful girl across the room. It turns out Wilson knows her. "She's the new barista at my coffee shop. She's getting her Masters in finance."
But Wilson says she's awful at her job: no matter what he orders, she always adds whipped cream, even when he specifically says he doesn't want it. House tells him that means she's into him. Wilson agrees to go talk to her, and House watches from a distance. It looks like things are going OK, and Wilson leans in to tell her something. She nods her head and gets up to leave with Wilson. When he passes House, he tells him, "She said my coffee is not the only thing she'd like to put whipped cream on." House is so happy he orders Champagne for everyone in the bar, then promptly leaves.
Chase wheels Nadia into Elena's room. "Thank you, for saving my life," she says. Elena says she loves Nadia, and recalls fun times they had as kids at a lake. Nadia is enjoying the happy memories, too. "Maybe we could go back," Elena says. "When we're both recovered. I could drive us up there, we could get a cabin, and maybe rent a canoe." But while Elena is still thinking only of the good times, Nadia's mind is pulling up more unpleasant memories. Elena can see she's getting upset. "Nadia, are you OK?" Nadia throws up her hands. "Elena, I'm sorry, I can't do this." Elena is confused, and Chase wheels Nadia out of the room.
In the hallway, Chase says he understands now why she's a waitress, away from any friends and family. "You can't forgive anyone. I don't think you weigh anything. I think you're like a lot of people. You focus on the bad memories instead of the good." Nadia sighs and says she doesn't have a choice, but while she's talking, Chase notices her hand is moving. He asks her to put her hand in her lap, but it doesn't stop. "I'm not doing that," she says. Chase tells her it's an involuntary movement called choreia. And it means they still don't know what's wrong with her.
House is bouncing a rubber ball at Cuddy's place until she takes it from him. "Do you know if that OR nurse that Wilson liked ever broke up with her boyfriend?" House tells her he's working on a back-up plan in case the barista doesn't work out. "You've got to let that guy alone," she says. But House doesn't want Wilson to be alone. "Is that what this is about? You feel guilty because Wilson's the one who's alone and not you? You still don't think you deserve this?" House protests, but Cuddy tells him it's OK to enjoy what they have. "Your happiness doesn't take his away."
Just then House's cell phone rings. It's Foreman, calling to say that Nadia's choreia rules out a clotting disorder. They're back to square one. Masters says that if it's hit her brain, she might not have long to live. "So now the question becomes: will the sister show up at the funeral." Chase tells him about the attempted reconciliation. "The bad memories crowded out the good and she ran," he says. House doesn't understand why they can't figure out what's wrong with her. "The woman has all the information we need. She's a bottomless diagnostic library."
Masters thinks maybe they missed some lifestyle thing when they checked out her apartment. "Yeah, it's all muscle strain from doing her hundreds of jigsaw puzzles," Foreman says. He starts to suggest other tests, but House is more interested in the puzzles. "Do a peripheral blood smear. Look for acanthocytes. I'll be right in."
Back at the hospital, House is in Nadia's room. "So, jigsaw puzzles," he starts. Nadia says she finds them calming. "Have you ever left one unfinished?" he asks. "No, that would drive me crazy," she tells him. "Speaking of . . ." House says, and gently nudges the water cup on her tray. She immediately puts it back where it was. He goes to try again. "Why are you doing that?" Nadia asks, agitated. "The more important question is: why are you?" House says. She tells him it's just a habit. "It's a habit that COMPELS you in an OBSESSIVE way that's so bad it's a DISORDER." Nadia denies she has OCD. Chase explains: "Each brain with OCD has its own way of filtering it. Some people wash their hands and hoard TV Guides. You do puzzles and hoard memories."
House says what they thought was a gift was just Nadia obsessing over her own life. "The memory was just a symptom of a symptom of a larger disease. You have McLeod syndrome, a rare genetic disorder that affects the nervous system, blood and can cause OCD." There's no cure, but Chase says the symptoms can be managed with medication. He hesitates, but adds, "Best case scenario, you can live another twenty years." "If it's any solace," House tells her, "everybody dies alone. Probably isn't," and he heads for the door.
Foreman comes home and asks Taub how the test went. "Well, it's hard to choke when you have all the answers," he says, packing his things. Foreman says it's better to suck at taking one test, than to suck at saving peoples' lives. When Foreman comes in the living room, he sees a giant TV. "Rachel thought it was too big, and I can't keep it in my hotel room," Taub says. Foreman thanks Taub, and Taub thanks him back for helping with the test. "Hey, look," Foreman says, "I have the room. You could stay if you wanted to, just until you find your new place." Taub agrees, and sets his bags down.
Later, Chase goes to see Nadia. She says she's feeling better. "I don't believe what House said," he tells her. "I'm not even sure House believes it anymore. You said you didn't have a choice to be the way you are. Now you do." And he pulls out a small bottle of SSRIs. "They've been effective in treating OCD," he says. "You mean, lose my memory?" Nadia asks. Not entirely; it would just be more like everybody else's. "My memory is the only thing that has ever made me special," she says. Chase says if she wants to be special then it means being alone. He leaves the pills on her tray and walks out.
Wilson comes home and is surprised to find a mouse in his kitchen, then surprised to find another one, but less surprised to find House there, too. He says the mice are for Sarah. No, they're not poisoned. And he takes the ragweed he hid earlier and tosses it out the window. "So," House starts, "I want to hear all the dirty, dairy specific details of your night with Java the Slut."
Wilson tries to tell him a wild story, but can't go through with it. "I flaked. I walked her to her car and said goodnight. I will get back into it. You just need to give me a little more time." House agrees . . . to give him ten more days.
As the evening winds down, Nadia stares at the pills, then finally decides to take one. Foreman and Taub are drinking beers and playing video games in Foreman's apartment. Wilson settles in to sleep, with Sarah sleeping on his chest. And, in bed, Cuddy repositions herself closer to House and goes back to sleep, while House stares up at the ceiling.