Things are about to go from bad to worse for Chicago P.D.'s Jay Halstead (Jesse Lee Soffer) as he continues to struggle with PTSD stemming from his time served in Afghanistan, as well as that Lindsey-sized hole in his heart following her abrupt departure.

The winter premiere, titled "Rabbit Hole," will see the Central Intelligence detective headed down the path of self-destruction when his hard-partying with Camila (Anabelle Acosta) inadvertently lands him in the middle of a drug-related homicide. Willing to put his badge on the line in order to solve the case, he'll soon find himself forced to choose between her and his loyalty to his unit.

"His spiraling will definitely continue," showrunner Rick Eid tells TV Guide. "I guess he probably hits rock bottom in that episode, and then we'll see if he can get out of it."

According to Eid, things will quickly "come to a head" in his relationship with Camila, who still doesn't know Halstead's true identity since they met while he was working undercover for a case. However, that could all change very soon, the showrunner teased.

But Halstead isn't the only detective harboring secrets. Ruzek (Patrick John Flueger) may also be forced to come clean about his undercover assignment from Denny Woods (Mykelti Williamson) when Voight (Jason Beghe) finally learns the identity of the mole in his unit. Whether or not Ruzek will be the one to tell him remains to be seen, but it looks like we're in for some major drama in the back half of the season.

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Chicago P.D. returns Wednesday, Jan. 3 at 10/9c on NBC.

Jesse Lee Soffer, Anabella Acosta; Chicago P.D.