Chicago P.D.

Sean O'Neal surprises Upton with a call from prison, revealing sensitive information; while Upton grapples with how to keep O'Neal at a distance, the team quickly mobilizes to stop a crime in progress before it's too late.

A shocking ambush at a funeral leads the team into a heated investigation to find the shooters; much to Atwater's surprise, he must rely on someone from his past to help in the investigation, dredging up old memories and revealing new truths.

A series of brutal home invasion robberies finds the team paired with Detective Borkowski, an old friend of Ruzek's, to work the case; things get complicated for Torres when it becomes clear Borkowski has a vastly different policing style.

After a shocking discovery, the team begins closing in on Sean O'Neal with every shred of evidence they can find; determined to keep his son out of prison, Chief O'Neal hires a lawyer.

To distract Intelligence from the investigation into his son, Chief O'Neal forces the team to handle a "dead fish" case; when that dead fish turns into a complicated heater case, Burgess is thrown back into difficult memories from her past.

When actionable evidence finally surfaces against Sean O'Neal, Upton and the team work relentlessly to build a case in secret; they discover Sean is more elusive and dangerous than anticipated.

Atwater's reactions during a tense arrest are called into question; the team must dig in to uncover key evidence that could aid in the ongoing investigation and clear Atwater's name.

Upton's dogged pursuit of a missing teenage girl leads the team into a dark web of human trafficking; chief O'Neal becomes involved with the unit's investigation when it becomes evident his son, Sean, has a connection to the missing girl.

A shocking murder pulls rookie officer Dante Torres into his own neighborhood; as Voight and Atwater help him navigate the case and manage tricky personal dynamics with wary neighbors, Torres realizes his life may be forever changed.

The team investigates a string of brutal pharmacy robberies, and Halstead connects with one of the victims about their Army careers; Upton suspects there is more to the story and confides in Voight.

When a convicted murderer hijacks a prison van, the team scrambles to find him and the abducted prison guard before it's too late; Burgess questions Ruzek's motives in a case, creating tension between the two.

Still reeling from the death of informant Anna, Voight faces a new threat as he tries to keep the neighborhood clean; new wrinkles develop in the Upton, Halstead and Voight dynamic; the team gets a new chief.