Don Took

Michael is so smitten with Gob's girlfriend that he decides to let her know that Gob has been cheating on her, and Lucille tries to break up Buster and Lucille Austero.

Vaughn unexpectedly gives Sydney a Christmas gift, Jack must save Sydney's life when she is suspected of being the SD-6 mole and the order has been given to torture and kill her, and Will begins to research SD-6.

Sydney must make a deal with Sark in order to obtain the antidote to Vaughn's potentially fatal illness. Will's research uncovers troubling inconsistencies involving 20-year-old IQ tests.

Vaughn asks Sydney to exploit her friendship with Sloane's wife to gain access to a mysterious Rambaldi book, and Will is kidnapped.

Sloane begins to question where Noah's true loyalties lie after he kindles romance with Sydney, Sydney uncovers startling information about her mum, and K-Directorate dispatches an assassin known as the Snowman to eliminate Khasinau.

Ariana Kane tracks Sydney in hopes of snaring her fugitive father, and Jack enlists Irina's help in finding Sloane's blackmailer.