8:30 PM (II) (S01E12)

The Intelligence Unit is on a mission to track down the bombers. While federal agencies collaborate, Voight and his team leverage their unique resources and contacts for leads. Lindsay and Antonio interrogate the surgeons involved in a transplant operation for a Syrian ambassador, but they come up empty-handed. Olinsky uncovers valuable information that propels the investigation forward. As they race against the clock, they discover the potential for more bombs set to explode. Meanwhile, Burgess keeps a vigil for her niece, whose fate hangs in the balance. The crossover begins in Chicago Fire S02E20 A Dark Day (I).