Former Chicago Firestar Monica Raymund, whose last appearance was in the season seven premiere, returns to the Windy City in Wednesday's fall finale, and the reunion between exes Dawson and Matthew Casey (Jesse Spencer) is fraught with tension. ET premieres a sneak peek at Raymund's first scene from the episode, titled "Best Friend Magic," where Dawson -- in town for a fancy charity gala -- surprises a stunned Casey outside the firehouse as she marvels over the statue commemorating Otis' death.
"It's beautiful," Dawson tells Casey, who is still speechless at his ex-wife's unexpected presence, in ET's first look from the episode.
"Boden called it sacred ground," Casey says, their attempt at small talk not exactly cutting it for the lieutenant. After all, there's some unfinished business the divorced couple has to tend to.
When Casey asks when she got into town, Dawson reveals that she arrived an hour ago and that the firehouse was her first stop -- possibly to see a certain someone whose initials start with M and end with C.
"I wanted to see...," Dawson begins to say, but she's cut off by a call for an emergency fire rescue. Of course.
As Casey runs back to the firehouse to suit up, his excitement is notable as he tells her not to go anywhere. "Brett's here," Casey exclaims, bringing up Dawson's former partner and his current maybe love interest. "Everyone's gonna wanna see ya!"
Back during the OneChicago press day in October, Spencer subtly dropped hints that Raymund's return was coming. Her character left the Chicago Fire Department for a permanent volunteer position in Puerto Rico, effectively ending her marriage to Casey.
"She ran down to Puerto Rico and I mean, how long is she really gonna be down there?" he coyly teased to ET Live's Cassie DiLaura, hinting that things may be complicated by the whole Brett factor. "Then it's going to be awkward!"
ET recently spoke with Chicago Fire showrunner Derek Haas about bringing Dawson back for one more -- and hopefully not last -- time.
"We were planning it from the very beginning of the season. When I had written the scene at the end of the premiere episode this season, where Boden is dedicating this memorial to Otis and he says, 'If you see somebody standing down here at this memorial, I want you to walk down this apron and bring the memorial to life.' And just the image of Gabby from behind and Casey walking out on the apparatus floor and seeing her there, that's where it started," Haas told ET. "It was pitched right from the beginning and pitched to [executive producer] Dick [Wolf] and he liked the idea. So then I had to text Monica and beg her to come back again. She was like, 'You're nothing if not persistent.' I said, 'Yes, that's true. I am. So come do it.' We were thrilled that she did it."
"For me creatively, it's inspiring to get to write for Monica because you know she's going to make anything that you write for her better than what you had in your head. She's just been like that the six years that I got to work with her," he continued. "You sit down to your computer and you know you're going to get to write Dawson coming back. It was awesome. Then, of course, she was delightful as always on set. It's just so fun writing for her. I mean, writing for her is a blast."