Criminal Minds: "Our Darkest Hour" -- Agent Prentiss (Paget Brewster) works with the rest of the BAU team to find a serial killer who preys on his victims in the dark, the fifth season finale cliffhanger of CRIMINAL MINDS, Wednesday, May 26 (9:00-10:00 PM, ET/PT) on the CBS Television Network. Photo: Monty Brinton/CBS ©2010 CBS Broadcasting Inc. All Rights Reserved.