Guest Appearances

Cristina, back from her honeymoon trip, searches in vain for Burke; Meredith, Cristina, Izzie and Alex spend their first day as residents with their own groups of interns.

Patrick Jane, Agent Lisbon and CBI agents investigate the murder of a successful criminal attorney whose only client is one of California’s most dangerous and powerful motorcycle gangs.

The identity of the Ice Truck Killer does not sit well with Dexter; Rita's ex-husband returns.

Sam, Dean and Bobby deal with the aftermath of the devil (Mark Pellegrino) rising from hell; Chuck has stunning news for the brothers.

Sam and Dean are kidnapped by a group of gods and held hostage as bargaining chips to stop the apocalypse.

Dexter follows clues in his rescue attempt; Rita's ex tries to convince her that Dexter is too dangerous.

Dexter finds himself unable to kill his victims; Debra returns to work.

The NATs of Quantico finally reach their graduation day; Alex and her team are faced with the terrorist.

Driven to the breaking point by Lucifer, Sam ends up in a mental hospital; Dean's plea for help leads him to a healer with the face of an old friend.

The NATs practice surveillance with Miranda and her troubled son; Shelby tries to keep Caleb at arm's length, while Raina allows Simon closer; Alex gets help when she tries to hack an FBI computer.

An explosive assignment results in some new agent trainees being sent home; as Alex continues working to clear her name, she encounters Raina and Nimah, who provide more questions than answers.

A former agent and profiler tasks the trainees with looking at serial killer cases and finding the victim who doesn't fit in; an FBI team interrogates Alex; Ryan's life hangs in the balance.

The Ice Truck Killer lures Dexter into a trap by kidnapping someone close to him.

The Ice Truck Killer leaves Dexter the most-awful crime scene imaginable, forcing him to confront a suppressed memory.

A high-profile woman's presumed suicide reveals a strange pattern of murders, leading Dexter to stalk a killer unlike any other.

Rita, Debra and Rudy join Dexter for a weekend away when he learns that his biological father has just passed away.

The BAU team hunts for a serial killer who targets members of the police department in Phoenix in a case that hits close to home for Morgan, a former cop.

A hostage rescue-training exercise makes Alex question whether she should leave Quantico; Alex finds a clue that puts the innocence of one of her closest classmates into question.

Sam and Dean begin to explore what Jack is capable of doing with his powers; an unexpected visit from Donatello alerts the brothers to the fact that Jack will need more protection than they can provide.

The NATS look forward to graduation and heading to their real world assignments; Alex learns someone she cared about in the past isn't who she thought.