“Chicago Fire”, “P.D.” and “Med” Teaser Offers a First Look at Dermot Mulroney's New Chief: 'Let's Hit It, Team!' (Exclusive)

NBC's OneChicago promo also offers a first glimpse at the new doctor on 'Med,' played by Sarah Ramos

All the kids heading back to school can only mean one thing for Wednesday nights: It's time to return to Chicago!

In an exclusive teaser for the new seasons of Chicago Med, Chicago Fire and Chicago P.D., all the fan-favorite characters are getting back to work and, in two cases, with some new costars.

The footage includes a first look at Dermot Mulroney as the new Fire Chief, named Dom Pascal, following Chief Wallace Boden's promotion to Deputy Commissioner of the entire Chicago Fire Department — and Eamonn Walker's departure at the end of Chicago Fire season 12.

Related: Chicago Fire's Jaw-Dropping Finale Sees Boden's Departure, More Changes at 51 and One Whopper of a Final Reveal

"Let's hit it, team!" Pascal says in one scene. In another, however, he notes, "There's going to be changes around the firehouse." Uh oh.

Kelly Severide (Taylor Kinney) isn't exactly feeling it. "There's something about the new chief that's a little off."

Related: Chicago Med Shake-Up: Dominic Rains to Depart After 5 Seasons as Dr. Crockett Marcel

In the footage from season 10 of Chicago Med, Sharon Goodwin (S. Epatha Merkerson), the Executive Director of Patient and Medical Services, declares, "We need to rethink how this ED operates."

In the next Med scene, Dr. Dean Archer (Steven Weber) isn't exactly getting along with new staffer Dr. Caitlin Lenox (Sarah Ramos). "How old are you?" Archer asks with skeptical judgment.

"How old are you?" Lenox snaps back.

Meanwhile, in the bits from season 12 of Chicago P.D., Hank Voight (Jason Beghe) is apparently working himself to the bone following the season 11 finale incident that nearly killed him.

"I'm the police. I'm doing my job," he insists. Later, when someone points out that he "almost died in that basement," he counters, "But I didn't. I'm still here."

While she doesn't appear in this first footage, Toya Turner will be joining the Intelligence Unit this season as Officer Kiana Cook following the departure of Tracy Spiridakos as Hailey Upton last season.

Related: Chicago P.D. Alums Tracy Spiridakos and Jesse Lee Soffer Fuel Romance Rumors with Latest Reunion

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Chicago Wednesdays kick off Sept. 25 on NBC with Chicago Med at 8 p.m. ET/PT, followed by Chicago Fire at 9 p.m. ET/PT and Chicago P.D. at 10 p.m. ET/PT.

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