After a slew of brutal slayings, District 21, led by Sergeant Hank Voight go after a Columbian drug cartel cleaning house in Chicago. They discover D’Anthony who proves to be an asset in the investigation. At District, complicated histories and unit rivalries surface which could end up costing them one of their own. Meanwhile, Rookie Kyle Ruzek is pulled from the police academy by Olinski to join the team.

Voight and Antonio enlist the help of agents at the Special Victims Unit in New York, Fin and Rollins, to help track down the culprit of a series of rape/murders. Burgess has an opportunity to prove herself to Intelligence. Elsewhere Lindsay enlists the help of Halstead to act as her date for her high school reunion to get back at an old rival.

The crossover starts on Law & Order: Special Victims Unit S15E15 Comic Perversion (I).

Lindsay goes undercover to catch a rogue cop who targets women at casinos. Platt risks her life in a negotiation crisis.

When Burgess and Lindsay respond to a call about a stabbing, the assailant turns out to be a kidnapping victim escaping her captor; Ruzek accuses Roman of having feelings for Burgess.

Intelligence investigates a string of bombings targeting members of the media. Racing against a ticking clock, the team enlists Firehouse 51 to help examine the devices and prevent the next attack.

The crossover continues on Chicago Fire S06E013 Hiding Not Seeking (II).

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).

After zeroing in on the suspect responsible for the bioterrorism that’s gripping Chicago, the PD prepares to undertake their biggest manhunt yet. Upton is torn between helping track down the perp and providing emotional support to the scared young girl that needs her. Voight fears his team is being sent on a wild goose chase.

The crossover starts on Chicago Fire S08E04 Infection (I) and Chicago Med S05E04 Infection, Part II (II).