A murderous Santa wreaks havoc on Briarcliff. Sister Jude faces off with the Devil. Arden has a shocking encounter in the Death Chute.

As Oliver and Helena grow closer, Oliver trains her to be his ally, complete with showing her how to use a crossbow. Diggle disapproves of Oliver sharing his secret with Helena as he’s not sure she can be trusted, but Oliver refuses to listen to his concerns. Helena’s quest for revenge proves to be too strong for Oliver to handle after she kills the head of the Triad and all hell breaks loose.

At the site of a train accident, Peter Mills becomes deeply upset when he observes the dead body of a young victim. Unable to shake his emotional distress about the event, he questions his future as a firefighter. Dawson and Shay save a 6-year-old girl whose mother is abusing her – but their confrontation leads the woman to resort to dire actions. Meanwhile, Severide aggravates his injury while rescuing a heart attack victim and Shay sends Clarice, her married, pregnant ex-girlfriend, back home to her husband.

A ritualistic killer is hunted after male bodies are found that have been physically altered. Meanwhile, Reid gets anxious at the prospect of meeting his mystery woman.

From "This is 40," actor Albert Brooks; musical guests Diana Krall

A man goes on a killing spree, but he has links to a prostitute that Benson encountered in an earlier investigation, so the FBI contacts SVU for information.

Rayna needs to take a look at what’s really important to her after hearing Teddy’s side of the story about Peggy; Juliette feels a sense of belonging with Sean’s family that she has never experienced before; Gunnar risks his partnership with Scarlett when he confesses his feelings; and music producer Dominic Wells invites Avery to Atlanta to work together while Deacon gets an amazing offer to tour -- but both opportunities come with a price.

Sam asks a hunter named Martin to keep an eye on Benny without telling Dean. However, when Martin tells Sam there was a vampire kill and he thinks Benny is responsible, Dean defends his friend. When Martin decides to take things into his own hands, things get messy and Dean is forced to make a very hard decision.

Hobbit Week honors Denny's, the Senate votes down universal disability rights, and Andy Serkis compares "The Lord of the Rings" Gollum to "The Hobbit" Gollum.

From "Suburgatory", actress Cheryl Hines; NPR host Peter Sagal; musician Richie Sambora as The Late Late Show House Band.

Mike helps his brother Rusty move some furniture into the Heck family's garage, only to realize the furniture is stolen; Frankie hopes to land a part-time job in a department store so she can get a discount on Christmas presents.

The chefs' culinary skills are tested at Seattle's Pike Place Market. Included: They must please palates with rare ingredients.