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.

The first three-hour crossover in more than five years unites the crews from 'Chicago Fire,' 'Chicago P.D.' and 'Chicago Med.'

The highly-anticipated three-hour crossover event known as One Chicago is extending fans a unique opportunity to participate in the drama from the comfort of their own homes. NBC’s special TV event, which brings together the storylines and characters of Chicago Fire,

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