The district is in a state of change - Lindsay has moved to New York- and the CPD is under scrutiny about the corrupt nature of its institution. Under the watchful eye of the city, the team attempts to bust a gun deal that quickly turns dicey when innocent civilians and children get involved. Tension erupts when Chief brings in Denny Woods to review the shootout, and Halstead becomes a key player in the outcome of the case.

A picture perfect family is shot dead in their home and the team goes in search of a drug dealer with a likely connection. Voight asks for the help of Vice Sergeant Sean McGrady who has an old beef with Upton. When McGrady turns up dead during the investigation, the case takes an unlikely turn.

Using information from Chicago Fire's Cruz, Intelligence chases down the robbery crew that’s been using the lockbox key. Voight is under pressure to bring the crew to justice without tarnishing the reputation of a murdered firefighter who might have been involved.

The crossover starts on Chicago Fire S07E15 What I Saw (I).

Voight and the Intelligence Unit focus all their effort and resources into investigating the disappearance of an exotic dancer who served as a long-time criminal informant for their team