A famous writer named Fletcher Stone toasts an outgoing magazine editor named Greta. He collapses during his speech, but when he comes to he can only speak gibberish, using completely incorrect words in sentences.
At the hospital, Cuddy asks Foreman to recommend a diagnostic department since House is currently out of town. Fletcher had a blow to the head followed by aphasia. Foreman sarcastically recommends another neurologist - one that House wanted to hire until he saw Foreman's credentials. Cuddy relents and gives Foreman the file.
Foreman and team begin the examination. Fletcher thinks he's speaking normally, but when he searches for a word he picks the wrong one. He has also lost the ability to write, which is called agraphia. Greta arrives at the hospital and tells the doctors that Fletcher didn't trip. He simply keeled over.
House and Stacy go to Baltimore to prepare for a Medicaid billing hearing. Stacy advises him not to defend his ridiculous billing practices. The administrator, noting that House rated all of his cases as fives on the difficulty scale, decides that Medicaid will have to examine every single case.
Chase and Cameron chafe under Foreman's leadership. They believe that the blunt trauma caused everything, but Foreman wonders if a stroke occurred beforehand. The doctors draw blood and hook up an EEG in search of a clot that could have possibly moved to the brain. Fletcher begins to struggle for breath and his O2 stats drop. The doctors rush to intubate.
Looking at an x-ray, Foreman notices fluid in Fletcher's lungs. A seizure could not have caused both aphasia and fluid in the lungs. The stroke could not have caused those symptoms either, unless Fletcher suffered from an abnormal heart rhythm. Chase hands Foreman a fax indicating that Fletcher's urine tested positive for amphetamines, which do not cause pulmonary edema unless they are smoked. Fletcher claimed in one of his books that he gave up drugs and changed his life. Could he be lying?
House turns to Wilson for the scoop because Cuddy called him about the case. Wilson tells him about the tox screen and that Fletcher's high temperature. House thinks that this rules out drugs. Foreman throws out encephalitis and meningitis as the obvious suspect. He recommends a course of antibiotics. Cameron wonders if it's an autoimmune disease. House calls the team and asks why they haven't called him for advice.
House orders antibiotics for meningitis and encephalitis, saying that the team will be screwed if it turns out to be autoimmune deficiency. He demands an MRI and a family history for genetic issues. After House hangs up, Cameron reminds Foreman who's really in charge. The team begins to interview Fletcher, his wife and his former editor for a recent history. Chase sends Fletcher through the MRI. The scan shows a little brain swelling and scarring, but not in the area that's currently affected by aphasia.
Back in Baltimore, a blizzard has delayed House's flight. Although she intentionally booked a later flight home to avoid him, Stacy runs into House in the airport.
Chase says that if Fletcher has meningitis, they need to do a lumbar puncture to identify it. Foreman says that if they are doing an LP on a patient with edema it could paralyze him. Cameron wants to know what House thinks, but Foreman reports that House's cell phone is out of service. They need more information in order to act, so Foreman suggests breaking into Fletcher's place.
At the airport, House continues asking Stacy about her crucifix. He has noticed that she wasn't wearing it earlier and he knows that she's never gone a day without it. She refuses to answer.
Later that night, Foreman and Chase pore through Fletcher's office, finding caffeine pills and amphetamines. This matches up with Fletcher's admission. They also uncover Topamax, an anticonvulsant that wasn't even prescribed to him. Chase wonders if they should check the home as well, but Foreman knows that Fletcher's wife is there. Chase wonders if she's hiding something. They check the house and find nothing.
In Baltimore, House continues to hector Stacy about the crucifix. She tells him to drop it. When she realizes that such an anomaly is driving House crazy, she decides to torment him by keeping quiet. Stacy finally blurts out that she and Mark had a fight, causing her to rush out of the house prematurely. She is becoming aware that Mark is slowly pushing her out of his life by constantly fighting about nothing. Feeling guilty, House now tries to console her.
Cameron is summoned to Fletcher's room. He's in pain and holding up a fork. She guesses that he has a metallic taste in his mouth. Wilson calls Stacy's cell looking for House. He lets him know that Fletcher has a metallic taste and kidney failure. House phones his now-stumped team. Foreman again suggests the lumbar puncture, but House warns them that they have to do it perfectly. He also chides the team for being too gentle with Fletcher. They need to care him with the likelihood of death because it's the only way they'll get the truth.
Foreman and Chase meet with Fletcher and his wife to instill fear into him. He denies holding anything back. Cameron performs the LP. Fletcher quickly rolls over and tries to confess something to her, but he only manages to say, "I couldn't tackle the bear! They took my stain!"
At the airport, an announcement is made that no flights will be arriving or departing until the next morning. Stacy, who booked a room at the airport hotel, invites House because his leg can't handle sleeping on a cot. Up in the room, House tries to find out exactly where their relationship stands. She explains that they're like spicy curry: House is abrasive and strong like the chili peppers, but no matter how much you love hot curry, it will eventually burn your mouth. You avoid it for awhile until you start craving it again. House and Stacy kiss.
The phone rings, and the doctors report that the LP showed an infection. Cameron pipes up that Fletcher tried to confess something to her, and House tries to figure out the meanings of "bear" and "stain." The word Fletcher actually wants to use could be related to those words by meaning or by sounds. They could also simply mean nothing.
The doctors begin throwing words at Fletcher to translate stain and bear. Pain? Brain? Bare naked? Fletcher repeatedly shakes his head. In Baltimore, House sits alone in an abandoned airport corridor. He's written Fletcher's phrases on the wall and stares at them, searching for a meaning. Stacy comes down to join him.
House calls the doctors to see what they've learned. Cameron points out that Fletcher mentioned stain once before, during the MRI. She thinks maybe he can only tell them things when his wife isn't in the room. The doctors wake Cuddy up so they can bring her in to distract Fletcher's wife.
Later that morning, Stacy finds House to let him know that his plane has been boarding for 20 minutes. He ignores her and calls the hospital, where he's patched through to Fletcher's room. He reiterates that they took his stain, and Foreman runs down the list of words they've assembled. Fletcher says yes to brain. House has a realization - bear means polar bear. Fletcher nods that he is bipolar. That would explain the Topamax, the risky job and the drug use.
House posits that Fletcher had to hide his bipolar disorder to maintain his job. When he fell in love, he wanted that life and was forced to make a change. House mentions bilateral cingulotomy, a surgical procedure that some people claim helps mood disorders. As House talks, Fletcher pounds the bed. House says that it wasn't the surgery, but a bug Fletcher picked up on his trip to South America for the surgery.
Fletcher's wife slips into the room. She wants to know if this is all true. House forges on and tells his team to get some blood on a slide under a microscope. Foreman spots cerebral malaria. Although a person with a microscope could have picked this up immediately, computers can't. Foreman chides himself for the misstep. Cameron tries to reassure him, saying they live in an electronic age.
At the airport, Stacy and House prepare to board their plane. Discussing Fletcher's case, they bring up that sometimes people want to change so badly for love but simply can't. People also need that love. So what to do?