The team are dispatched to a destroyer to probe the bizarre death of a sailor, discovering he was deeply immersed in an addictive fantasy role-playing game and may have been bent on exacting revenge on his arch rival.
A former agent and profiler tasks the trainees with looking at serial killer cases and find the victim who doesn't fit; an FBI team interrogates Alex; and Ryan's life hangs in the balance.
More questions arise when the Grand Central Station bombers are revealed. Back at Quantico, the recruits receive time off for the holidays.
Lilly and Scott decide to reopen the cold case of a wealthy family matriarch found dead in 1998, when new evidence comes to light suggesting that she was murdered.
At the Abbey Sister Amy makes a bargain for immortality, while in the woods the race is on to find the Bleeding Tree now that Kyle is infected.