A 16-year-old high school student, Dan, starts suffering night terrors and frequent hallucinations after playing lacrosse at school. The parents take him to Dr. House after receiving a letter that Cameron sent in House's name and House begins a bet to determine whether they are his biological parents. After Dan exhibits more symptoms, including a myoclonic twitch and a blocked blood vessel, House diagnoses Dan. Dan suffers from an auditory hallucination during a procedure, however, ruling out House's diagnosis. Using the coffee cups from the parents, House does a paternity test and discovers that neither parent is biologically related to Dan. When he remembers a case he had earlier, when the mother of a baby did not want vaccination for her child, he theorizes that Dan is suffering from a measles virus contracted during his childhood. House confirms his diagnosis with a retinal biopsy and successfully cures Dan.