House finds himself in a strip club with a head wound and no memory of the last four hours. Outside, he finds the bus crash he got the injury from. He heads to PPTH with most of the rest of the crash victims (some go to another hospital across town, but we don't care about them), and the only thing he knows for sure is that someone is going to die if he can't remember what he saw on the bus. He's sure it was a symptom of a disease and demands to examine all of the crash victims to find it again, even trapping them in the ER under a meningitis quarantine to do so. Hypnosis, smelling passengers' clothing, and a lie-down in a sensory deprivation tank help him piece things together somewhat, but they also make his head injury (which ends up being a skull fracture) worse. So while he figures out that the patient he's looking for is the bus driver and the symptom was a shuffling gait indicative of Parkinson's, he also bleeds out of his ear, barfs all over Cuddy's shoes and passes out, only to wake up in his house with a nurse and a guard, both of whom have strict orders from Cuddy to keep House resting. He has no intention of following those orders, especially when he realizes that his diagnosis was wrong and the bus driver is getting worse; his liver is failing and he can't breathe.

Cuddy gives in and brings House back to PPTH, where he notices the driver's dental caps that are indicative of recent dental surgery and locks everyone out of the room except the driver and Biana, who almost got a real name in the episode but didn't. (Cuddy called her "Dr. Hadley" but then House said Cuddy got the name wrong) Biana is faced with a choice; either go along with House's diagnosis that an air bubble from the dental drill has been moving through the driver's body and must be removed by stabbing the guy in the heart with a syringe, or unlock the door so PPTH's other doctors can work their magic. The wrong choice means the driver will die. When the stakes are this high, you have to go with House, even with a head wound. Biana does, and he was right. The driver will be fine and House can go back to his apartment, now guarded by Cuddy (who, by the way, did a striptease in House's fantasy at one point during this episode and got nakeder than the actual stripper in the first scene). Except that he can't sleep, because he keeps seeing a woman on the bus who looks out of place with her expensive clothes and who won't leave him alone. He realizes that the mystery has not been solved after all; the air bubble was released into the driver's body upon the impact of the crash, not before. The symptom he noticed wasn't the shuffling gait, and it didn't come from the driver.

House herds everyone onto a bus with pictures of the passengers around their necks to try to reenact the scene and jog his memory, and he takes some special pills for Alzheimer's patients to rev that jog up to a sprint. And here begins what might have been the best ten minutes I've ever seen on television: he's back on the bus, and the woman in expensive clothing is there. She's wearing a necklace and keeps asking House to tell her what it's made of. And we realize it just before House does -- it's amber. Amber. The mystery woman is CTB! And then all hell breaks loose as the bus crashes and CTB is tossed around along with the rest of the passengers and House. When they land, she's got a spike through her leg, her face is a wreck, and she's cold. House ties off the leg wound and passes out. He wakes up to see them taking CTB away and he follows her out of the bus. And then we realize that House went and died on the reenactment bus, thanks to those pills, and Wilson and Cuddy are doing CPR on him. His heart starts back up and he looks at Wilson and tells him CTB was on the bus. Wilson doesn't believe him until he realizes that CTB hasn't returned his phone calls. And Biana looks at the patient chart of a Jane Doe who was sent to that hospital after the crash and it matches CTB's description perfectly, down to the birthmark on her shoulder. What was she doing on that bus? Why was she with House? And is she even still alive? The Best Show on Television will be back next week with another episode to hopefully answer all of these questions.