While helping a depressed Morgan spy on Anna, Chuck flashes on her boyfriend; Jeff and Lester beg Ellie to hire them to play at her wedding.

While Chuck and Sarah go on to rescue Steve they realize they have a chemistry together. Meanwhile Morgan becomes a pariah at the Buy More after mistakenly getting Emmett promoted.

Chuck gets a new mission when Sarah's best friend Carina comes through town with her fiancé Karl. Things get complicated when Chuck wants to hash out his and Sarah's relationship problems while they're on the mission. Meanwhile, Morgan finds himself in trouble when he lies to Jeff and Lester.

Chuck, Sarah and Shaw reunite to find the Ring operative behind the death of Shaw's wife. Sarah has faith that Shaw is ready for the mission but Chuck is worried about his emotional stability. Meanwhile, Morgan considers leaving the Buy More.

The mission to take down Volkoff reaches a dangerous new level, while big changes loom at home. As Sarah works to free Chuck’s mom, Chuck and Morgan embark on their own mission to take down Alexei Volkoff. Meanwhile, Casey bonds with his daughter, Alex, while Ellie tries to ease Awesome’s anxieties over fatherhood.

Chuck and Sarah’s wedding prep includes one final detail: ensuring that the mother-of-the-groom makes it to the ceremony alive. Meanwhile, Morgan’s responsibilities as Best Man include his most dangerous mission yet, as he faces Vivian Volkoff. Elsewhere, Ellie tends to the last details of the rehearsal dinner and seeks help from an unlikely source.

Chuck and Sarah learn who is trying to destroy Carmichael Industries. Ellie's Christmas plans come undone. A computer virus threatens to ruin Christmas at Buy More.