Carnell Hall and his father Ken celebrate Carnell's graduation from Princeton. Ken thinks Carnell's mother would have been so proud of him. That night, Carnell enjoys one last frat party. He begins to feel a series of electric shocks before convulsing on the floor.
Wilson leads House's team through Carnell's symptoms -- painful shocks, headaches, nausea and drowsiness. House glances at the board and immediately tosses off possible explanations. Wilson shoots down each with already completed test results. Aside from the obvious diseases, House thinks something is missing. They need to find out what it is.
Cameron, Chase and Foreman run a battery of tests, but still come up empty. They report to House that there is nothing missing. House directs them to examine the fatal car accident that killed the patient's mother several years ago. In broad daylight, she veered off a straight road. House wants a DNA analysis.
Foreman swabs the inside of Carnell's cheek and tells him they're checking for NF2, an inherited disease that causes abnormal growths on the cranial nerves. The doctors witness Carnell defecating in his bed, but he had no idea that he did it. He didn't feel a thing. Back in House's office, sphincter paralysis has been added to the white board. That, combined with shocks, usually equals Miller Fisher syndrome. Yet Chase points out that a stool sample testing negative for botulinism rules that out. Foreman mentions that the DNA test revealed no NF2 markers.
Foreman throws out transverse myelitis, which could have caused the symptoms. They don't know, however, what is causing the transverse myelitis. Foreman wonders if the infection is gone but the memory of it remains in the body -- as in molecular mimicry. House likes this idea, and orders an immunoglobulin level and an electrophoresis.
House gets a call from his own mother. She and his father have a long layover in Newark, but House tells her that he already has dinner plans. While Foreman and Chase draw cerebrospinal fluid from Carnell, Cameron peels off and tells Wilson about the House parents coming to town. She wants him to invite them as a surprise.
Carnell asks his father to get him a soda. While he's gone, Carnell confesses to the doctors that he recently went to Jamaica with some friends. House thinks maybe Carnell got exposed to some pesticides, possibly through smoking marijuana. House orders them to start Carnell on an IV of pralidoxime. Foreman chafes because there is no evidence to support a poisoning diagnosis.
In the parking lot that night, House accuses Wilson of going behind his back to invite his parents over for dinner. Wilson reluctantly admits that he did. If House doesn't tell his parents the truth, then Wilson plans to see him at seven for dinner.
The next morning, Cuddy and Foreman drop in on Carnell, only to find him voraciously eating breakfast. They're amazed that the treatment is working, but the shocks have only decreased and not disappeared completely. His white blood cell count is still low. House is alerted that Carnell has the chills and his temperature has spiked up to 106. House admits to Ken that he has no idea what's happening to his son.
House adds fever to the white board. The team is stumped. Carnell wasn't actually recovering but merely feeling better. Yesterday he had no fever or infection. House orders antibiotics and another round of tests. He also orders Cameron to track down Carnell's friends that made the Jamaica trip.
House catches up with Cuddy to volunteer for clinic duty. However, she is aware of the dinner plans and will be attending Wilson's party as well. Cuddy implores House to just go to dinner because it will make his mother happy. He replies that it's not his mom who's the problem. It's his father.
Cameron reports that one of Carnell's friends had a rash, but nobody else had any health issues. House has her bring the friend Taddy in so they can have a look at him. Cuddy instructs Cameron to let House believe that his parents arrived early so that he will visit the rash-stricken Taddy himself. Just then, Chase and Foreman find Carnell bleeding into his abdomen. They rush him into surgery.
The infection has caused a perforation in the colon, which means the antibiotics aren't working. Cameron begins to lie to House about his parents when Cuddy enters with news -- Carnell's friend Taddy began vomiting blood and will be delivered by ambulance within ten minutes.
When Taddy is wheeled in, House immediately cuts open the boy's pants and asks if he and Carnell had sex in Jamaica. Taddy denies this, and explains that he only took Carnell away as a break from working in his dad's scrap metal junkyard. This gives House an epiphany and he rushes off to Carnell's room. House asks Ken about any odd scrap Carnell might have handled recently. Ken says he found an old plumb and put it on a key chain for Carnell so he'd always remember where he came from. House demands to know where it is.
After Cameron discovers that Carnell's old clothes are in a bureau, Houses orders Chase and Foreman to take the bureau to radiology without opening it. House runs a Geiger counter over the bureau and it goes crazy. Foreman later explains to Ken that the piece of metal was radioactive, and anybody who had contact with it will need immediate treatment for Radiation Sickness by transfusion. Carnell had so much exposure that he's going to need a bone marrow transplant. Additionally, there's a tumor inside his spinal cord which is causing the symptoms.
A surgeon should be able to remove the tumor, but surgery on somebody as hemopoetically compromised as Carnell is very risky. Carnell is wheeled off to a sterile isolation room. House's parents arrive and visit him in the office. He tells them he can't make it to dinner tonight, but they persuade him to have a quick sandwich in the cafeteria.
The surgeon successfully removes the tumor but Carnell begins hemorrhaging. In the waiting room, Chase gives Ken the news that Carnell will not likely be able to fight off infections because his white cell count keeps falling. After surgery, Ken visits Carnell in the sterile room. Carnell tells his father that he's scared. Ken says that he will be fine and has nothing to fear.