Chicago P.D. Finale Video: Atwater Gets a Troubling Blast From the Past

Atwater’s new partner is his worst nightmare: On this Wednesday’s Chicago P.D. season finale (NBC, 10/9c), the officer goes undercover and discovers that Tom Doyle (guest star Mickey O’Sullivan), the cop who pointed a gun at his head last season, is already in deep with the gun-trafficking ring Intelligence is trying to take down.

Forced to work together despite their troubled past, Atwater and Doyle — who’s been promoted to detective — go for a ride, which quickly turns problematic when Doyle once again starts to racially profile someone in TVLine’s exclusive sneak peek.

“That guy over there with the bag looks suspicious,” Doyle says, pointing out a pedestrian with a large duffel bag.

“Why? Because he’s black?” Atwater counters.

Doyle assumes that the man is headed to a drug den, because “it is what it is. That is a brother in a known gang zone, carrying a bag, walking into a stash house.” But he doesn’t stop there: Doyle gets out of the car and starts questioning the man, even as Atwater yells at him to let it go. When gunfire then erupts, things go from bad to worse.

Press PLAY above to watch the sneak peek, then hit the comments with your hopes for the finale.

GET MORE: Exclusive, Finales, OneChicago, Video