A gun-toting man from the ER waiting room takes House, Thirteen and a few patients from the waiting room hostage in Cuddy's office. The man claims to have a long undiagnosed illness, and demands attention from the best doctor in the hospital. With a room full of patients, House uses them as guinea pigs to assure the gunman that the medications he plans to use are legitimate. The team and Cuddy communicate with House over the phone, to run tests and offer diagnoses. When one hostage is shot, Thirteen puts her own health on the line, as she simultaneously receives the treatments the hostage is getting. House is determined to diagnose the hostage-taker, but the SWAT team's plan to put an end to the standoff, may put the entire room at risk.