A father and his son, Carnell, a Princeton student, are celebrating the son's graduation and they have a tender moment. Carnell is heading out to a party where he gets drunk with his friends, but feels electrical shocks and starts going into convulsions as something happens within his spine.
At the clinic, Carnell is still in serious condition and Wilson is running the differential because House comes in late. House has to take the case because he owes Wilson for a $5,000 loan, and suspects recreational drugs, but the tests and treatment prove negative. House concludes something is missing and tells his staff to find out what it is they've missed. Carnell reveals he had Ecstasy but then goes into another round of convulsions, and his history provides no clues. Foreman suspects whatever he has is related to his heavy drinking, while House reveals he used the $5,000 to buy a motorcycle, then gets himself invited to dinner at Wilson's. House tells them to check up on Carnell's dead mother's car accident 15 years ago. Wilson reveals his wife isn't speaking to him and he reluctantly agrees to the dinner.
The staff check for the genetic component but Carnell is unaware that his mother died in a car accident she caused – his father Ken covered it up and told him it was a drunk driving accident so Carnell would stay away from alcohol. Carnell then unwittingly has a bowel movement – he has sphincter paralysis.
The DNA test doesn't reveal any markers and then House takes a call to lie to his mom that he can't meet with her and his father as they're passing through and have a layover. Foreman suspects a molecular memory of an earlier virus along the spinal cord and House orders more tests. Cameron approaches Wilson who considers canceling the dinner but Cameron convinces him to invite the parents. Carnell isn't happy with his father for lying but then reveals he went on a trip to Jamaica without his dad's knowledge. House concludes he was smoking marijuana but may have been exposed to a pesticide despite the lack of evidence.
House figures out Wilson invited his parents and isn't happy, and reveals he's been testing Wilson with increasing money loans, and offers to pay him back the loan if he cancels the dinner. Wilson takes the money and tells House to cancel it himself.
Cuddy isn't happy with House's lack of evidence for the poisoning diagnosis but Carnell is showing marked improvement and House is satisfied until Carnell goes into a new series of convulsions. Now Carnell has a fever and infection, because of a reduced white-cell count. They give him broad-range antibiotics and send Cameron to find the guys Carnell went to Jamaica with. She approaches Carnell who is reluctant to discuss it in front of his father. The father isn't happy about being kept out of the loop and Carnell reveals he went to Jamaica.
House meets with Cuddy and apologies for letting his duties at the clinic go…so he can work the next night and get out of the dinner. She refuses and is going to be there herself. Cameron meets with Carnell's friend Taddy and reveals he has a fungus on his groin, and Cameron takes a sample. No one else has health issues and House wants Taddy brought in, and House tells her to get him in by telling him he has a life-threatening illness. Carnell starts bleeding into his abdomen and they take him into surgery – the infection is responsible and House orders more antibiotics. Taddy starts vomiting blood and they have him brought in, where House discovers Carnell walked at a scrap metal yard owned by his father – Ken lied and said he was a construction worker. House confronts him and the father reveals he gave Carnell a lead plum on a keychain, but doesn't know where it is now. House sends Foreman and Chase to get the bureau where the key chain is – he's figured the plum is radioactive and confirms it with a Geiger counter.
After confirming Carnell has a tumor in his spine, they determine they need a bone marrow transplant but the surgery will be risky due to his weakened immune system. House's parents arrive and insist he meet with them for a sandwich in the cafeteria. During surgery Carnell's heart rate and blood pressure drop, while Cameron and Foreman look on as House chats with his parents. House's father clearly isn't thrilled with his son's life.
Wilson is meeting with Ken when Chase comes in to update them on the surgery and there is another intestinal perforation ad his white count is falling. Chase reveals there's nothing they can give Carnell to fight off the infection. Cameron gives House the news and he thanks her for not getting involved, then tells her that he's an only child and that his dad is like Cameron and insists on honesty…even with his son. Ken meets with his son and they reconcile over their mutual lies…but then he lies that Carnell will be fine.
Cameron talks with Wilson about House and the fact his dad thinks he's a disappointment, and gets on his motorcycle and heads off into the night.