Criminal Minds: Season 10, Episode 1

10 - 1: 'X'

The BAU team investigates a series of murders in Bakersfield, Calif., which have left the victims unidentifiable. Also, the team welcomes new agent Kate Callahan into the BAU fold, who assists them in their efforts in solving the cases. Jennifer Love Hewitt joins the cast as Kate Callahan, a seasoned FBI undercover agent who becomes the newest BAU member.