The highly anticipated three-show cross-over will finally happen when "Chicago Fire" season 4 returns after its midseason finale.

Firefighter Christopher Hermann's (David Eigenberg) life remains in peril after Freddie (Ralph Rodriguez) stabbed him and left him for dead. But is it really the end for the owner of Molly's?

According to speculations, an explosive event will happen when the second part of "Chicago Fire" season 4B premieres next year. Could Hermann's health condition bring together the cast of the show as well as several characters from "Chicago P.D." and "Chicago Med?"

In a previous interview with The Hollywood Reporter, series showrunner Matt Olmstead talked about the possible scenario for the crossover episode.

"The one personal piece of storytelling it unearths is Voight's backstory with his late wife. We've established that she died years prior to when he appeared on Fire, but not the circumstances of her death and what Voight has to deal with in terms of dealing with that memory." Olmstead said. "Also, it affects Lindsay because, as stated in the script, as much as her mom Bunny was unreliable, not there, problematic, Voight's wife was the perfect model for who she wanted to be as a woman."

Olmstead also explained that since Voight was deeply affected by his wife's passing, they never bothered to make a new love interest for the character.

The series showrunner also clarified the rumors about a bigger four-series crossover in February, saying that it could possibly not happen soon because it will be too close to the earlier crossover event.

"I think we are in the process of dialing that down to just a Chicago P.D.-SVU crossover," the series creator shared. "With how ambitious we're being with this three-way crossover, we might just downsize it to what's worked in the past with the crossover between the two cop shows. There's a great chemistry there."

The "Chicago Fire" season 4 midseason premiere is scheduled to air on Jan. 5 on NBC.