The team investigates a murder in which the victim appears to have been wearing a CPD-issued wire. Burgess works a case with a new partner. Crowley questions Lindsay about the night that Intelligence pursued Justin's killer.

Intelligence investigates when a young man is beaten and his fiancée is apparently abducted. Lindsay surprises Halsted with a big question. Cdr. Fogel takes Platt to task for going over his head to have Tay assigned to District 21.

A car plows through a crowd outside of a concert venue and is followed by gunfire, sparking fears that it may be terror-related. Burgess spots Atwater's brother where he shouldn't be. The team works to bring peace to the community before more blood is shed.

The team hunts drug dealers selling fentanyl, which has been linked to multiple overdoses around the city. Tay and Burgess discover a bloodied child who shares a twisted secret about his home life. Mouse contemplates reenlisting in the Army. Platt informs Tay about her next assignment.