Dr. Jennifer Keller's body is inadvertently taken over by a cunning thief, Neeva Casol. While Neeva tries to escape Atlantis, Keller finds herself imprisoned with a death sentence on another planet, forcing the team into a race against time to return Keller to her original body before she is put to death.
Phyllis' Moroccan-themed holiday party goes up in flames when Meredith's hair catches on fire and Michael is forced to deal with the accident. Meanwhile, Dwight corners the market on the hottest toy of the Christmas season.
Mr Merdle's death and the collapse of Merdle's Bank sends shockwaves through London as thousands face financial ruin. Arthur returns to the Marshalsea a prisoner, Amy goes back to her birthplace to look after him as he lies gravely ill, and Rigaud returns to play out his blackmail in the Clennam house.
As Christmas nears, Liz's parents ditch her for a couples-only retreat, leaving her all alone for the holiday. Because of this, Liz decides to work for a charity program, "Letters to Santa." Meanwhile, Jack takes his frustration out on the staff after his dream holiday is ruined.
As preparations get under way for the school's cultural festival, Ryūji urges Taiga to consider reconciling with her estranged father.
When a new murder leads to a connection with an infamous serial killer, Grissom secretly joins the class of well-known criminal pathologist Dr. Raymond Langston to gain access to the killer and get a crack in the case.
A package for Morris from his deceased father is delivered to the ER. Sam has some anxiety over Alex being removed from the ventilator. A woman with a high-risk pregnancy worries that she will be deported. An old friend returns to celebrate the holidays.
As Ash continues training for his gym battle. Dawn tries to train with her newly evolved Piloswine, and learns that her Pokemon isn't as receptive as its non-evolved form.
Earl discovers that Joy has continued a holiday scam they started years before, and has expanded the scam to include her friends.
For the quickfire, chefs must identify ingredients in a dish. For the elimination challenge, the contestants cater a bridal shower for judge Gail Simmons.
Mr Dorrit returns to Venice, a broken man, after a visit to London revives unwelcome memories. Arthur warns his mother that she may be in danger from Rigaud. And Amy and Arthur meet again.
Filled with love for Carmelita, newly-elected Senator Patrick Darling goes against Nick and Tripp's advice and invites her to his inauguration. Meanwhile Chase defies his agreement with the Darlings and threatens to go public with his accusation that Patrick murdered his sister; Jeremy finds out that Simon has control of Nola's little brother; as Andrea's health dims, Brian promises God anything to make her well again; and Karen goes to Nick's apartment to make amends with him, but is confronted by a gun-wielding intruder.
The parent company of Christine and Barb's gym franchise comes for an inspection and discovers that they have broken a contractual clause, risking the entire business. New Christine wants Richard to get a vasectomy.
A food bank delivery man is found murdered and buried up to his neck, surrounded by flower petals in a backyard. Crews and Reese believe the incident may be related to a cult from the 1970s. Crews confronts Mickey Rayborn, despite warnings from the FBI.
The BAU team hunts for a serial killer who targets members of the police department in Phoenix, Ariz., a case that hits close to home for Morgan, a former cop.
Pacific Wellcare, Charlotte's practice opens, and the competition with Oceanside Wellness starts; Dell suggests that an in-house adoption program should be created.
Chuck and Ned deal with the shocking return of someone from their past; Emerson and Olive investigate the death of a lighthouse keeper.