The One Chicago television universe will be coming together once more for an explosive case that will put more than one of their lives in danger.
Known for staging crossovers regularly on the series, producers tease this two-night event will be like nothing fans of Chicago P.D. and Chicago Fire fans have seen the show stage before.
"I know we do these little crossovers," Chicago Fire showrunner Derek Haas said to TV Guide. "Here's your big, two-hour, all-the-characters-are-involved crossover."
Scroll through to find out everything we know about the upcoming crossover event.
'CHICAGO P.D.' CELEBRATES A MILESTONE
The crossover event will hold a special occasion, as Wednesday night's episode marks P.D.'s 100th episode, which was what inspired the big event in the first place.
The decision makes sense as P.D. started on Fire with Voight (Jason Beghe), Jay Halstead (Jesse Lee Soffer) and Antonio (Jon Seda) all appearing in major storylines during Fire's first season.
P.D.'s hour will focus on a journalist who seeks revenge on the person spreading lies about him on the internet, forcing the Intelligence crew to step in.
"Intelligence investigates a string of bombings targeting members of the media. Racing against a ticking clock, the team enlists Firehouse 51 to help examine the devices and prevent the next attack," reads the synopsis for P.D.'s half of the special, released by NBC.
As the investigation intensifies, the police officers will enlist the help of their firefighter colleagues of Firehouse 51.
During the Fire hour, Dawson (Monica Raymond) and Brett (Kara Killmer) will be going undercover a Voight and Antonio track down the bombing suspect.
"As the investigation continues, Boden (Eamonn Walker), Casey (Jesse Spencer) and Severide (Taylor Kinney) lend their skilled expertise in the investigation," the synopsis for the Fire hour said.
Chicago P.D. boss Rick Eid teased the crossover will see characters who have rarely interacted in the past get stuck together during the event.
Among them will be the unlikely team-up of P.D.'s Voight and Fire's Boden, who will find themselves holed up together in a surveillance van. The results will most likely make fans of the show laugh during the tense hours.
Producers spilled the beans on the upcoming episodes with TVLine and revealed the doctors of Chicago Med were sadly unavailable for this crossover.
"We were on weird schedules," Haas said. "It all has to do with when we can get on their stage... for this crossover, we just did P.D. and Fire."
However Med did stage a mini-crossover of sorts during Tuesday's episode as Jay Halstead stopped by the hospital to investigate a stabbing.
The Chicago Fire star, who plays the role of firefighter Matthew Casey, chatted with Access Hollywood about the crossover.
"They've got this serial bomber who's on the loose, they're trying to catch him and Boden is there a lot with Voight," Spencer said. "They also bring in Dawson and Brett to distract [a suspect] while Russek goes to his computer to get evidence."
He teased that Casey will definitely be concerned to see his wife Dawson get closed to a suspect, but teases that the final scene of the Fire episode is one not to be missed.
"That's when me and Severide get to do something..." he teased.
Chicago P.D. sergeant Trudy Platt will be in the line of fire during the tense event.
According to Christian Stolte, who plays Randall "Mouch" McHolland on Chicago Fire teased his TV wife will find herself in danger.
"My lovely TV wife gets BLOWN UP tonight on Chicago PD, and if you think 'm going to sit back and watch that happen, well then, you must've read the script," Stolte tweeted Wednesday.
My lovely TV wife gets BLOWN UP tonight on Chicago PD, and if you think I’m just going to sit back and watch that happen, well then, you must’ve read the script. #ChicagoFire pic.twitter.com/ftF9EIvy35— Christian Stolte (@ChristianStolte) March 7, 2018
Jon Seda sat down with TV Guide, teasing the case surrounding the crossover will affect Antonio in a personal way, as he deals with a teenage daughter whose life is well-documented online.
"It affects him big time because his daughter, it's her generation more so than his that's growing up with social media and that's how they express themselves. She gets caught up in some things that, from the surface, look to be something that Antonio needs to dig deep into his parenting skills to try to cope with it," Seda said.
Eid and Haas revealed the crossover is more "integrated" than typical One Chicago crossover episodes.
"..I feel like this one might be the most integrated, where it's truly a two-hour story that integrates all the characters." Eid said to TVLine. "It's not a hand-off. It's more a two-hour story that combines the elements of Chicago P.D. and Chicago Fire."
"It's just really like a movie," Haas added "...It, for sure, is the most cast-mixed of all of them, where you're seeing your favorites from Chicago Fire in that first hour, just integrated throughout and seamlessly... It was so much fun making this one."
The crossover event will feature a moment fans of the franchise have been waiting to see since the beginning: Jay Halstead on a motorcycle.
"I've been wanting to do it for a hundred episodes," Haas revealed. "And finally, Rick, he tried to get me to not do it. He was like, 'Derek, I don't know that America’s ready for this,' and I said, 'I want Halstead on a motorcycle. The fans have demanded it. It’s happening!' [Laughs] So get ready for that one.
The two-night crossover event begins with Chicago P.D. on Wednesday at 10 p.m. ET followed by Chicago Fire on Thursday at 10 p.m. ET on NBC.