The following reveals major plot points from tonight’s NBC’s One Chicago crossover. NBC’s Chicago Med, Chicago Fire and Chicago P.D. came together for an epic crossover event taking the franchise to the next level.

LaRoyce Hawkins of "Chicago PD," "Chicago Fire's" Miranda Rae Mayo, and Darren Barnet from "Chicago Med" talk about the first Wednesday night "One Chicago" crossover event in more than five years. The casts of all three shows will combine for a full three hours of pulse-pounding prime time action.

After five years, the One Chicago franchise finally has another three-part crossover event airing tonight, and the bosses previewed what’s in store. Beginning with Chicago Fire at 8 p.m. ET, the event’s official logline reads,

It's been five years since the last three-part Chicago Fire, Med, and P.D. crossover. This one did not disappoint.

There's an explosion near a government building, which causes the ensemble casts of all three One Chicago shows to arrive on the scene. There are injured and trapped victims all a