The BAU team investigates a series of murders in Bakersfield, Ca, which have left the victims unidentifiable. New agent Kate Callahan joins the BAU fold, and assists in the effort to solve the cases.

When a prominent attorney goes missing in Boston, the BAU unearths secrets in his past which could point to the reasons for his disappearance.

Victims in California have the BAU searching for an UnSub who may have witnessed abuse as a child. Meanwhile, Kate shows parental concern when her niece, Meg, makes a date with a friend to meet a boy they met online.

The BAU is called to Wisconsin in search of a serial killer, and the team looks for a connection among the victims for clues to the UnSub. Also, Kate has trouble dealing with her niece, Meg, when she begins acting out.

When Kate's niece and her best friend Markayla are kidnapped, the BAU suspects an online predator engaged in sex trafficking who poses as a teenage boy.