Hooten's mentor, Dr. Arvin Wayne, walks into the wrong procedure on the wrong day, leading the surgeons at Chelsea General to question the cognitive abilities of one of the hospital's elder statesmen. When a top competitive swimmer suffers a seizure in the emergency room, Villanueva follows his gut – leading to a surprising diagnosis. Tina must perform a risky transvenous thrombolysis with Ty and Michelle's help. And Sydney implies that Lieberman might be a crummy doctor for missing the signs of bacterial endocarditis in a former patient.

Ty and Tina receive a late night call from Afghanistan, where Corpsman Jacob Gold desperately needs help when his fellow Marine suffers a traumatic head injury. Sydney believes a happy infant's unnatural laughter is related to an undiagnosed neurological problem. And Sung and Hooten attempt to reconcile the husband and sister of a brain-dead gay patient, only to find themselves caught in the legal crosshairs of the situation.