Mission to track down a computer super virus leads Chuck to return to his roots as a hacker -- and to call on his biggest competition, Gertrude Verbanksi, for help. Elsewhere, a new Buy More employee complicates Jeff and Lester's friendship.

Chuck and Sarah discover who's behind the plot to destroy Carmichael Industries. Meanwhile, Ellie's plans for a perfect Christmas begin to come apart. At the Buy More, Morgan and the gang must fend off angry customers as a computer virus threatens to ruin Christmas.