The new year does not get off to a very good start for Kelly Severide (Taylor Kinney). When Chicago Fireand Chicago P.D. return with a double-episode crossover on Jan. 3, Severide is the prime suspect in a crime that no one - not even Severide himself - knows for sure if he committed.

Put in the awkward position of taking Severide into custody is his former flame Erin Lindsay (Sophia Bush). But while their romance is a thing of the past, the connection they once shared may cloud Lindsay's ability to do her job.

"There are some feelings there," Chicago P.D. showrunner Matt Olmstead tells us. "Because of those feelings she'd want to help him out and perhaps go too far."

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Needless to say, that doesn't sit well with Lindsay's current boyfriend, Halstead (Jesse Lee Soffer), who takes the opposite approach. "He's in a bit of a rush to lock [Severide] up," Olmstead teases. "Is he a little too quick to judge or assume this guy is guilty because he knows that he slept with his current girlfriend? [He's] accusing Lindsay of maybe falling over herself to assume that Severide's not guilty."

By the end of the episode, we'll know for sure whether Severide's guilty or not; but regardless of where the investigation leads, the damage to Linstead may already be done.

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