SPOILER ALERT: The following reveals major plot points from the One Chicago 3-episode crossover event airing March 3.

Here's what members of the 21st District have been up to since the show began in 2014.

Andrea Newman, Allen MacDonald and Gwen Sigan dissect tonight’s #OneChicago action-packed, emotional crossover event.

It was an explosive One Chicago crossover between Chicago Med , Chicago Fire, and Chicago P.D. after the death of beloved ...

Chicago P.D. icon Hailey Upton ( Tracy Spiridakos) made her triumphant return during the three-part crossover event with Chicago Fire and Chicago Med, and viewers were delighted to see she's been ...