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.

Atwater goes undercover to bring down the longtime head of a criminal enterprise and becomes entangled in a situation that tests his allegiances as well as his conscience.

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

A mayoral candidate is shot by an unidentified sniper, and Intelligence races to catch the shooter before he can take out his next target.

With the threat of a gang war looming, Voight and Ray Price must organize a peace summit to end the bloodshed before more innocent people get hurt. Burgess evaluates her future with Blair.

Intelligence's investigation into the murder of Burgess' boyfriend threatens to reveal a dark side she was unaware of. The real motivation for his murder uncovers a much more unsettling truth.

Atwater goes undercover to take down a gun-trafficking ring, but discovers an officer from his past is undercover in the same organization.