When a clinic patient claims to have an appointment with the diagnostic department, House is skeptical of the letter which he himself supposedly wrote to the family.
House suggests that the night terrors were a result in post-traumatic stress disorder from sexual abuse and his double vision was caused by a concussion and/or eye strain.
None of the tests show why the night terrors occurred, but House finds a large blockage in one of Dan's brain ventricles.
House remembers a baby he treated earlier whose mother did not want to vaccinate the child and hypothesizes that infant Dan may have caught the measles virus, which remained latent for 16 years.
Dan recovers fully after brain surgery and reveals that he already knew he was adopted because he has a cleft chin while his parents don’t, but that he does not care.
The doctors have difficulty explaining this treatment, with the story examining the problem of obtaining informed consent in complex cases.