A gang shootout results in a flood of victims in the ER. John tries to halt the escalating violence, but to succeed he must navigate rival gang members and the police. Meanwhile, Gretchen tends to the young woman who sparked the bloodshed.

Ellison scrambles to locate Antoine when the boy disappears from his bed at the surgical center; and Polk tries to convince a patient to lie about her medical condition in order to keep John out of their supervisors' crosshairs.

John visits Antoine's father, the leader of the VCC gang, in prison, and tries to disentangle himself from his responsibilities with Antoine. Meanwhile, things get out of control when Gretchen confronts Hillary's abusive boyfriend at his home.

John wants to help Gretchen, but doesn't want to circumvent the law; and Samantha's doubts about John are increased by information provided to her by Kyle.

Detective Holden forces John to testify against the gang, drawing its ire; Samantha's past threatens her marriage.

John and Gretchen's plans to get Antoine home are interrupted; John must do everything in his power to save his family.

Gretchen makes expensive arrangements to hide Antoine in order to prevent Bridget from learning that John illegally transferred him to the surgical center. That means John needs to ask the gang for money, however. In other events, a past indiscretion tests John's relationship with Samantha.

Det. Holden of the Gang Task Force questions John about his suspicious activity; and Gretchen travels to the gang neighborhood to save a young boy.

The drama about a disillusioned ER doctor opens with Ellison saving the life of a young boy when he intervenes in a drive-by shooting and ends up in the middle of a gang war.

John tries to rein in his compulsions, but is tested when he's tipped off about an impending massacre. Samantha, meanwhile, turns to Det. Holden for answers.