The One Chicago universe pulled off the unthinkable: integrating over 20 characters into one thrilling and coherent storyline. In a three-hour event involving Chicago PD, Fire, and Med, the writers achieved a resounding success with the crossover on NBC,

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.

T he One Chicago universe is about to experience an unprecedented crossover event, promising to be the most ambitious in the franchise's history. For the first time, on January 29