On tonight’s Chicago Fire, the episode is pulling double duty. Not only does the episode serve as the fall finale, but it’s also the landmark 100th episode.

Co-creators and executive producers Derek Haas and Michael Brandt talked to TVLine about what to expect in tonight’s episode. Brandt said that everyone from Firehouse 51 is safe when the fall finale ends (in years past, finales, both fall and season, have left the fates of characters up in the air) but there’s still an intense finale.

“It’s not a life-and-death cliffhanger, but it’s the equivalent of one,” Brandt said.

Haas said that Dawson (Monica Raymund) has “been fast-tracked for permanency placement, and so the question of adopting (Louie) becomes the driving force of the episode.”

And after the episode last week where Dawson found out her parents are getting divorced after 40 years of marriage, she could use all the good news she can get.

Severide (Taylor Kinney) also has a major plotline in the episode where he really starts to think about his life and whether he wants to carry on in his bachelor-for-life lifestyle that he’s led in all of the episodes of the show.

Haas said that the speech that Herrmann (David Eigenberg) makes at Molly’s centennial is the speech that he (Haas) and Brandt want to say to all of the cast, crew and viewers “(about what) these 100 episodes have meant to us.”

Haas also talked to The Hollywood Reporter as a way to look back on the show for the past 100 episodes. He said that Chicago Fire was his and Brandt’s first attempt at writing a television show, as the two had worked on 2 Fast 2 Furious and 3:10 to Yuma together.

“We were having so much fun making the show that nobody told us we had to worry about ratings and all of these things. The first episode came out and it did OK. The second episode was way worse and I honestly thought we were dead in the water. We just thought, ‘Oh, OK, that was an interesting six months or year of our lives, but it was fun while it lasted,'” Haas said.

Luckily, he said the seventh episode of the first season is where things started to really turn around for the show.

He also said that Shay’s (Lauren German) death was the hardest thing that the show has done and that he thinks Mouch (Christian Stolte) is the character that has changed the most since the show started in 2012.

Haas said that the whole “One Chicago” universe, which consists of Chicago Fire, Chicago P.D., Chicago Med and the upcoming Chicago Justice, was entirely Dick Wolf’s idea and that Wolf started pushing for a spinoff midway through the first season. Haas said that NBC then gave the first season of Chicago Fire a total of 24 episodes, which is how they were have the backdoor pilot for Chicago P.D. as the second-to-last episode of the first season.

And, as for Molly’s, the home away home for not only the firefighters of Firehouse 51, but also the detectives at the Intelligent Unit, the doctors of Gaffney Chicago Medical Center and the Cook County States Attorneys, came about from executive producer Matt Olmstead saying they all needed a place to hang out after shifts.

They originally filmed the bar scenes for Molly’s at Lotties Pub in the Bucktown neighborhood of Chicago, but eventually had to build their own interior because it was getting too hard to film in the actual bar.

But fans of the show will be pleased to know that the interior and exterior looks extremely similar to Molly’s on the show. The signature twinkle lights are strung up in the ceiling of Lotties and Lotties has a sign up outside their door that says “Molly’s by day, Lotties by night.”

This morning, the Chicago Fire Twitter page posted a video of some of the members of the cast talking about the 100th episode, with many of them saying they’re lucky to be a part of an amazing cast and family.

Firehouse 51 wouldn't be the same without you! Who's ready for #ChicagoFire100? pic.twitter.com/mrdj0mI5TU

— Chicago Fire (@NBCChicagoFire) December 6, 2016

The 100th episode of Chicago Fire airs tonight, Dec. 6, at 10 p.m. on NBC.