A disillusioned ER doctor, who finds his existence transformed when he intervenes in a drive-by shooting, saving a young boy's life and killing one of his attackers. When he learned the boy is still marked for death, he finds himself compelled to save him.

John must find a missing patient, or face the consequences of losing a gang leader's son; Gretchen tries to convince a patient to lie about her medical condition in order to keep John clear of their supervisor's suspicions.

To keep Bridget from finding out that John illegally transferred Antoine to the Surgical Center, Gretchen makes expensive arrangements to hide the child elsewhere. That forces John to ask the gang for money, and brings him closer to their world than ever before. Samantha's relationship with John is tested when a past indiscretion resurfaces.

When the victims of a gang shootout spill into the ER, John must navigate rival gang members and the police while trying to halt the escalating violence. Meanwhile, Gretchen tends to the young woman who sparked the recent bloodshed.

Detective Holden, of the Gang Task Force, grills John with questions about his suspicious activity. Meanwhile, Gretchen travels to the gang neighborhood to save a young boy.