The hit franchise is going big for its three-show crossover airing March 4 — and not just with the emergency (a plane going silent midair). Chicago P.D.‘s Jesse Lee Soffer and Tracy Spiridakos are reprising their roles as Jay Halstead and Hailey Upton; he exited in 2022, while she left in 2024. Now, Hailey is in the FBI, and Jay is working drug interdiction for the U.S. Army.

“It was especially gratifying having them return, to see how the dynamics between them have changed and also getting to see their point of view of our unit, of Voight [Jason Beghe], of our new characters, and how much we’ve changed, too,” previews P.D. exec producer Gwen Sigan.

As for what to expect from the fan-favorite couple, who were divorced as of the last time either was onscreen, nothing (especially the promo) suggests they’ve reunited. And Sigan says, “Both of them have lived entire years off-screen.”

Like with past crossovers, Med and Fire swap timeslots, so the action kicks off on the latter at 8/7c before concluding on P.D. While it begins with the plane emergency, that’s just the beginning. In the aftermath, the first responders realize there’s something else going on, leading to a bigger, deadlier mystery that could put many in jeopardy.

“We’ve never attacked anything as big as this plane incident before. The action is epic in scope, and yet at the same time, it’s the most character-driven crossover we’ve ever done, really tapping deep into the history of the main characters of the One Chicago world with the central mystery,” says Fire exec producer Andrea Newman.

Fire leads right into Med, with the former ending “with some people facing a sudden and unexpected health crisis that brings them to Gaffney in the second hour… including an expectant mother,” Med executive producer Allen MacDonald teases.

Then, in the third hour, “PD is against a ticking clock, knowing that if we don’t solve this case, and solve it fast, lives will be lost,” warns Sigan.

Does that mean our main team is in peril? Newman cautions viewers to stay vigilant: “These are front-liners, so absolutely, they are in danger from the jump.”

Scroll down to check out photos from all three episodes, then let us know in the comments section what you’re hoping to see in this year’s crossover.

One Chicago Crossover, Wednesday, March 4, 8/7c, NBC