A bus accident leaves dozens of passengers with injuries. House, who was also on the bus, suffers severe head trauma and, as a result, frequent bouts of amnesia. Although he is dazed and does not even know why he was on the bus in the first place, he experiences flashbacks in which he can see one of the passengers displaying signs of a deadly illness. But try as he might, House cannot remember which passenger it was or what he saw that led him to the obsessive conviction that one of the passengers is about to die.

With the hospital’s emergency room full of crash victims, House and his medical team face a unnerving race against time to establish for sure if any of the passengers’ lives really are in danger – or if House is merely suffering from the after-effects of his concussion.