The BAU team investigates an UnSub with striking similaritiesto Rossi's latest obsession, "The Chameleon",a.k.a. Everett Lynch, who nearly killed him and thendisappeared.
As they await news of Halstead's fate, the team turns theirattention to an illegal arms dealer. Atwater discovers hisbrother is in Chicago and could be tied to the case. Voightmust deal with Halstead's shooter. Burgess makes her decision.
Dex is hired by a famous TV judge to help find his prodigalbrother but soon finds that she is not the only one looking forhim. Elsewhere, after a carjacking under his watch, Hoffmanenlists Grey's help in tracking down the carjackers. Back athome, Dex isn't prepared for Ansel's unexpected news.
With a member of the BAU in the hospital, the team searchesfor Everett Lynch, and his daughter, Grace. Also, Spencerhas a meaningful visit with his mother, Diana Reid, whileshe's experiencing a period of lucidity.
New Year's Eve celebrations are cut short when a masked manstabs a woman in her own home. Jack and the team must uncoverthe identity of the mystery murderer before they strike again.
Gibbs must face the reality of his actions after he assistsZiva with "the one thing" she said she would need to take careof before returning to her family.
After being terminated from Chastain, Conrad has difficultyfiguring out his next step and distracts himself byaccompanying a patient on a zero-gravity adventure. In hisfirst move as the new Chief of Surgery, Cain puts the doctorson a commission-based pay system, which causes Devon's newintern to agree to a procedure before weighing the risks.Meanwhile, Mina struggles with taking care of Adaku's baby andBell's supplement company get its big break.