'Chicago Fire' Showrunner Teases 'Rough,' 'Devastating' and 'Brutal' Season 8 Premiere

Chicago Fire is heading toward tragedy after the deadly cliffhanger from the Season 7 finale. The episode dropped a few bombs on the characters and fans, including Severide (Taylor Kinney) and Stella (Miranda Rae Mayo) getting back together, a surprise engagement and more. But the biggest shocker of them all came at the end of the episode, when half of the firehouse was caught in a factory basement as the whole place was about to explode.

The Season 8 premiere, titled "Sacred Ground" will likely not miss a moment of the devastating action stemming from the explosion, with series showrunner, Derek Haas revealing the episode will not be easy for the characters.

"[The episode] going to be rough [and] devastating [and] as brutal as we've done in a premiere," Haas teased to TVLine, of the deadly incident. "It's going to have fallout that's going to stretch beyond the premiere."

Casey (Jesse Spencer) will be caught in the tragedy, which Haas called "more important matters" than worrying about Brett (Kara Killmer) accepting Chaplain Kyle's very public marriage proposal.

The aftermath of the catastrophe will see some shifting and changes in the firehouse, as Haas previewed Stella and Severide being "rocks for each other while they're dealing with other feelings and emotions and new responsibilities."

The producer also previewed the addition of a new firefighter to the team, following the department expanding the number of people who can be on a rig. The development will bring Blake Gallo (Shadowhunters alum Alberto Rosende) into the fold.

"He's a very energetic, high-risk firefighter they see from another company," Haas teased, "and [Casey, Severide and Herrman have to] decide, 'Would this guy be a good fit at 51?' Especially in the face of what we [see] in the first episode, that's going to be a question."

In the face of the tragic premiere, fans can look forward to an exciting upcoming crossover event for all three One Chicago shows, which will see Haas write all three episodes for the first time.

"Dick [Wolf] and I came up with the story, and then I'm writing the three episodes, which will be really fun," Haas told TVLine in early September. "I haven't written Med since we did the Med [spinoff] episode. But you'll see why that's feasible, because it's less about each show having its own shape to it and more like all three shows really intertwined throughout. You could be watching any hour and be like, 'Oh, wait, is this P.D.? Or is this Med? Or is this Fire?' We're even doing scenes that you would think would be a Med scene, but it's in the Fire hour."

"We were thinking of like Poseidon Adventure or like Independence Day," he said of the crossover's inspiration, "where you've got a bunch of stories — cutting to one, cutting to another — and there's a mystery, both medical and criminal, going on that we're trying to solve before it gets out of hand."

Chicago Fire will return with a new episode Wednesday, Sept. 25 at 9 p.m. ET on NBC.