There's a shift in show order for the crossover event. “Chicago Fire” will air first at 8 p.m., followed by “ Chicago Med “ at 9 p.m., with “ Chicago P.D .” concluding the event at 10 p.m.

NBC’s One Chicago is airing its first crossover in five years tonight. Here’s how to watch the epic event featuring "Chicago Fire," 'Chicago Med," and "Chicago P.D.."

The crossover starts at 8 p.m. with "Chicago Fire" followed by "Chicago Med" at 9 p.m. and "Chicago P.D." at 10 p.m.

Season 10 of Chicago Med has been gripping, and it's about to get all the more exciting with a three-part One Chicago crossover event. It's been five years since we've seen Gaffney's finest join forces with Chicago Fire's squad and P.