THE TWO-NIGHT EVENT! Chicago Fire kicks off the #OneChicago crossover as the two squads hunt down a killer arsonist. Spoiler: 2/04/15 Crossover episode, Night #2 (w/Chicago Fire) Chicago P.D. "A LITTLE DEVIL COMPLEX" 02/04/2015 (10:00PM - 11:00PM) (Wednesday) CONTINUED FROM Chicago Fire's "THREE BELLS," EPISODE, FIREHOUSE 51 ENLISTS INTELLIGENCE TO HELP CORNER THE ARSONIST THEY BELIEVE KILLED SHAY. Antonio (Jon Seda) and his sister Gabriela (guest star Monica Raymund) go to the office of Elliot Gish (guest star Robert Knepper), the man they believe started the fire that killed Shay. Intelligence along with patrol officers Burgess (Marina Squerciati) and Roman (Brian Geraghty) put pressure on Gish to try and make him confess. Lindsay (Sophia Bush) approaches Voight (Jason Beghe) about returning to Intelligence when she realizes that the task force isn't what she thought it would be. At the same time Desk Sgt. Platt (Amy Morton) is acting strange and has everyone curious as to why she's being overly cheery, friendly and nice. Also starring Jesse Lee Soffer, Patrick Flueger, Elias Koteas, and LaRoyce Hawkins. Eamonn Walker, Charlie Barnett and Markie Post guest star.