After tragedy strikes Intelligence, the unit must persevere during an adrenalized manhunt across the city.

With the suspects still at large and conditions worsening underground, first responders race to reach the trapped victims, while the investigation into the assailants comes into focus. The crossover starts on Chicago Fire S13E11 In the Trenches (I) and Chicago Med S10E11 In the Trenches (II).

The showdown with Deputy Chief Reid intensifies when Intelligence narrows in on Ortero.

The unit learns the truth about a secret Torres has been keeping, as Deputy Chief Charlie Reid puts a focus on Intelligence.

An unexpected visitor causes disruption for Ruzek and Burgess amidst an emotional investigation involving an unidentified young girl.

Assistant State's Attorney Chapman assists Intelligence with a sensitive investigation that drudges up painful memories for Voight.

Torres is haunted by his previous transgressions as Cook takes on a tense undercover assignment.

Ruzek grapples with his father's worsening condition while Intelligence searches for an elusive serial killer.

Voight questions Deputy Chief Reid's motives in enacting a Violence Reduction Initiative across a neighborhood where numerous gangs are fighting for territory.

A month after Voight's close brush with death, Intelligence is overwhelmed with cases as they catch a high-stakes drug bust.

In the midst of a momentous rainstorm, Intelligence lends support to Officer Cook when she and her partner disagree about an investigation.

Cook turns to her family when Intelligence faces administrative roadblocks that threaten a kidnapping investigation.

Ruzek witnesses a tragic accident on an icy bridge, leading Intelligence into a dark, sinister case involving sex trafficking.

Burgess' memory recall is put to the test following a deadly incident at her local diner.

Voight and Chapman work together to uncover Deputy Chief Reid's shadow dealings as Reid assigns Intelligence to a carjacking case.

Atwater struggles to find balance as he teams up with a forensic psychologist on an armed robbery case.

Burgess is put to the test as she looks to make an advancement in her career.

Intelligence makes a gruesome discovery that leads Torres to go undercover at the juvenile detention center where he served time as a teen.

The search for the suspect in a shooting uncovers a surprising personal connection to Atwater and Val, raising questions about their relationship status.

Cook works with a confidential informant for the first time in a robbery-murder case with links to a star college athlete.

A mounting street war threatens a community-center project that Atwater is trying to get off the ground.

Ruzek and Burgess’ wedding fast approaches, Chapman grows closer to Voight, and Torres faces the emotional fall out of his actions.