A diving competition is interrupted when a man with virulent bacterial meningitis collapses and causes an outbreak scare. Partially in an effort to avoid assisting with the quarantining, House examines a young diver named Mary (Skye McCole Bartusiak) from the meet, whose symptoms don't fit recent-onset meningitis. Foreman is assigned to help House but Chase, most likely as punishment for betraying him to Vogler, is sent to look up all potential causes for the most basic of Mary's symptoms: neck pain (which only happens when she twists her neck side to side).
Foreman runs myriad tests, as internal bleeding and absence seizures are added to Mary's symptoms, but turns up nothing. House theorizes that someone is trying to sabotage the talented diver, possibly by using rat poison. An ultrasound reveals intracranial bleeding, a new symptom. Finally, House realizes that Mary is pregnant at 12, and the pregnancy has caused thrombotic thrombocytopenic purpura. Although Mary is only 12, under New Jersey law House is not obligated to tell Mary's parents, so he tries to persuade Mary to tell them herself. She has the abortion and tells her parents the truth.
Meanwhile, Cuddy and Wilson both pressure House to hire a replacement for Cameron. After turning down several high quality candidates for minor flaws (such as their fashion sense) House is forced to admit that he really wants Cameron back. House goes to Cameron and asks her to come back, saying that he needs her to keep him in his place. Despite his best efforts to give her what she wants, however, Cameron agrees to return only if House will go out on a date with her. Though shocked, House agrees.