Keith Foster, a sixteen-year-old, has been bleeding internally for three weeks with no clear cause. While House works the case — ruling out drugs, infection, lupus, and cancer before landing on naphthalene poisoning from a termite nest inside the boy's bedroom walls — he is also mid-withdrawal, having accepted Cuddy's bet to go a week without Vicodin in exchange for a month off clinic duty. The diagnosis turns on a single detail: Keith hallucinates about his dead cat, House autopsies the animal, finds the same poison, and stops a liver transplant seconds before surgery.

The episode uses the medical case to put House's addiction under direct pressure. Every decision he makes is shadowed by the question of whether withdrawal is compromising his judgment, and the answer — he breaks his own fingers to manage the pain and still gets it right — m ...