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

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

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

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

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

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

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

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

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

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).

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

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

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.

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

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

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

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

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

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

Forced to cease operations while under investigation by Internal Affairs, Intelligence goes off-book to bring down Reid once and for all. Ruzek and Burgess consider delaying their nuptials amid the uncertainty.