Chicago Fire , Chicago P.D. and Chicago Med are reportedly set to film their first crossover episode in five years.

According to a new report published by TVLine on Wednesday, November 13, the One Chicago franchise is planning a one-night crossover event, which is due to air later this season. The storyline will reportedly center around a massive explosion in an office building that will require the services of the city’s fire, police and medical departments. There have been several crossover One Chicago episodes in the past, with the last time occurring in 2019 before several factors including Covid as well as WGA and SAG-AFTRA strikes make them logistically tricky to film.

The last crossover involved a biological terrorism event that brought all the Chicago teams together to face off against. Speaking to Forbes in 2019, Chicago Fire executive producer Derek Haus shared insight into the planning for the crossover episode, titled “Infection.” He revealed the inspiration came about after the One Chicago franchise’s creator, Dick Wolf, injured his foot and it was on the verge of becoming infected.

“At a kickoff dinner for this, Dick said, ‘I want to do a biological weapon story, like a flesh-eating bacteria,’ and I was like, ‘Okkkaaay,’” Haas told the outlet. “Then he said, ‘What if it happens at a Bears game,’ and I was like, ‘What if we have a tailgate and we get characters from the three shows and this random guy is walking by and he falls and you.