'Chicago P.D.'s Brian Geraghty on What Kept Roman Away Until the 'Fire' Crossover

Brian Geraghty One Chicago Return Fire PD Crossover
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When Sean Roman (Brian Geraghty, above) left for San Diego in Chicago P.D.'s Season 3 finale, the former police officer had a broken body (from a traumatic gunshot injury) and a broken heart after Officer Kim Burgess (Marina Squerciati) declined to leave with him. In tonight's two-show crossover, which marks Roman's return to the Windy City, he's looking for his younger sister, who has gone missing amid an epidemic of teen opioid overdoses.

"He selfishly hadn't come back earlier to help his sister because of his own ghosts," Geraghty says. "He felt that after his injury the police department had let him down, and there was [the bad parting between] him and Burgess."

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'There's still some love between them,' the star says of the former partners.

Hoping to avoid his former Intelligence Unit colleagues, Roman instead hits up firefighter pal Lt. Kelly Severide (Fire's Taylor Kinney) for info before launching his own investigation…which then leaves him no choice but to deal with his old boss, Sgt. Hank Voight (Jason Beghe). The awkwardness doesn't end there: In the second hour, Roman works the streets with Burgess, suffering her own heartbreak after a recent miscarriage, and the would-be father, his onetime antagonist Adam Ruzek (Patrick John Flueger).

Could the busy actor, currently appearing on USA's Briarpatch, see another P.D. visit ahead? "I suspect I'll be back," he says. "It's been a wonderful time."

Brian Geraghty Chicago PD Season 7 Episode 16 Return

(Matt Dinerstein/NBC)

Chicago Fire-P.D. Crossover, Wednesday, 9/8c, NBC