Dark days are coming in the next episodes of "Chicago Fire" season 4.

According to the synopsis for the fourth episode titled "You Day Is Coming," the entire Chicago Fire Department seems to be needing one another's support as they deal with a big disaster. Could this mean that one of their own will meet an untimely death?

The official synopsis reads:

"One of 51's own needs the support of the entire house to recover from a near disaster. Meanwhile, Herrmann (David Eigenberg) has to figure out a way to reopen Molly's after it gets shut down and Severide (Taylor Kinney) digs deeper into the arson investigation, while struggling to cope with one of his toughest days yet."

While there is no confirmation yet about the possible death of a major "Chicago Fire" character, it sure seems like the episode will feature a tough situation for the characters since Molly's means a lot to Herrmann, and it became a favorite hangout place for most of his colleagues in the fire department. It means that losing the bar could greatly affect the characters of the action drama series.

Meanwhile, series showrunner Matt Olmstead talked about the upcoming major crossovers of "Chicago Fire" with other NBC procedural dramas in a recent interview with The Hollywood Reporter.

According to Olmstead, they are still working on the plot that connects "Chicago Fire" with "Chicago P.D." and the new "Chicago Med" series that they are planning to premiere in January. But the main plot will reveal "Chicago P.D." Intelligence Unit head Hank Voight's (Jason Beghe) backstory involving his late wife who was previously talked about in "Chicago Fire" season 1 when he appeared in the cross-over episode titled "Let Her Go." However, the circumstances surrounding her death were not discussed in the episode.

Olmstead claimed that the story in the crossover episode will also affect P.D.'s detective Erin Lindsay (Sophia Bush), but he did not give any details about "Chicago Med's" involvement in the story.

"Chicago Fire" airs Tuesdays on NBC.