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

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.

The three-parter is called "In the Trenches," with the first responders of One Chicago's leg of the nine-show Dick Wolf TV universe racing into danger after a catastrophic gas exp

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.