Season 4 opens with Chuck engaging in a sweeping quest to find his mother (Linda Hamilton), all while keeping the rogue mission a secret from his sister. Meanwhile, Sarah and Casey journey to Russia to probe a mysterious organization and its operative (Dolph Lundgren); and Ellie breaks big news to the family. Olivia Munn and Harry Dean Stanton also guest star.
There are crimes of fashion when Chuck and Sarah go undercover in Milan for Fashion Week to seize a high-tech weapon, yet Chuck soon recognizes a flaw in his relationship with Sarah. Meanwhile, Morgan discovers a vulnerability about the new Buy More; and Casey futilely tries to make his home in Burbank. Karolina Kurkova, Lou Ferrigno and Isaiah Mustafa guest star.
Villainous nemeses Hugo Panzer ("Stone Cold" Steve Austin) and Heather Chandler (Nicole Richie) return to haunt (and hunt) Chuck and Sarah. The conniving Chandler, however, stirs up Chuck's curiosity when she claims she has information about his mother. Meanwhile, Morgan preps the store for an all-important video-game release. Stacy Keibler also guest stars.
Chuck and Sarah focus on improving their communication skills when they embark on a trip to a Latin American nation with Ellie and Awesome. While there, the foursome reunite with Premier Goya (Armand Assante), but danger soon follows. In Burbank, Morgan ventures into a forbidden romance. Tia Texada and Mekenna Melvin guest star.
Casey is shadowed by his past when his former team returns and searches for him. Meanwhile, Chuck continues his quest to find his mother, and Morgan tries to summon the courage to disclose a delicate secret to Casey. Guest stars include Eric Roberts, Joel David Moore, Dave Batista and Mekenna Melvin.
Team Bartowski battles a sinister scientist (Robert Englund) who is plotting to release toxins that induce nightmares. Meanwhile, the true allegiances of Chuck's mother (Linda Hamilton) come under scrutiny, and the Buy More gang celebrates Halloween. Morgan Fairchild also guest stars.
In the wake of his first fight with Sarah, Chuck embarks on a rogue mission, ultimately colliding with his mother's spy handler (Timothy Dalton) and an enigmatic Russian agent (Ana Gasteyer). Meanwhile, Ellie digs into her family's secretive past. Linda Hamilton guest stars.
Worried his relationship with Sarah is souring, Chuck tries to prove his worth by undertaking a perilous assignment with an overly ambitious agent (Rob Riggle). Elsewhere, Buy More staffers delve into Greta's true identity, prompting Morgan and Casey's swift interference. Richard Chamberlain and Summer Glau guest star.
When a shadowy international spy named the Belgian (Richard Chamberlain) inches closer to the truth of the Intersect, Team Bartowski slips deep into the jungles of Southeast Asia to thwart him, and Sarah sets forth on a rogue mission. Elsewhere, Ellie tries to unravel a family secret with help from Awesome.
A Thanksgiving-leftovers dinner is stuffed with complications for Chuck when his mother (Linda Hamilton) arrives. At Buy More, Morgan gears up for the busiest shopping day of the year while Jeff and Lester launch their latest scheme. Elsewhere, Ellie continues to uncover family clues left behind by her father. Timothy Dalton and Monet Mazur guest star.
Chuck embarks on two secret quests. As he tries to locate a nano-chip in the vineyards of France, he also attempts to stealthily concoct a romantic getaway for Sarah. Meanwhile, Lester pesters Big Mike to help him sort out his troubled love life.
Sarah sets out on a perilous undercover mission by assisting Mary Bartowski (Linda Hamilton) in a bid to finally crush criminal mastermind Volkoff (Timothy Dalton). Meanwhile, Ellie and Awesome bicker over baby names. Mekenna Melvin guest stars.
The operation to vanquish supreme evildoer Volkoff (Timothy Dalton) reaches dangerous new heights, as Sarah focuses on freeing Chuck's mother (Linda Hamilton) and Chuck teams up with Morgan for a mission. Meanwhile, Casey connects with his daughter (Mekenna Melvin); and Awesome's anxiety about fatherhood escalates.
Chuck, Sarah and Casey fly to Morocco in a bid to rescue suave agent Roan Montgomery (John Larroquette). Meanwhile, Chuck and Sarah lock horns over their future plans; Mary (Linda Hamilton) strengthens family ties; and Morgan anticipates meeting Alex's mother.
Chuck orchestrates Sarah's reunion with her former spy team, the C.A.T. Squad. The feline-quick team then try to take down their thuggish nemesis (Lou Diamond Phillips)---but simmering resentments and past secrets soon surface. Meanwhile, a C.A.T. member makes lusty moves on Morgan. Mini Anden and Mekenna Melvin guest star.
Valentine's Day is disrupted when Team Bartowski is ordered to protect a young heiress (Lauren Cohan) in England. Meanwhile, an enigmatic official (Robin Givens) makes an offer to Casey. Back home, Ellie and Awesome try to sort out a parenting issue; and Morgan mulls over a game-changing move. Mekenna Melvin guest stars.
Chuck and Sarah orchestrate an intricate heist at a high-security bank. Elsewhere, Vivian is thrust into the spy world; Chuck and Sarah's wedding plans heat up; and an unforeseen twist marks Morgan's search for a new roomie.
Chuck suspects that Casey may be embarking on secret missions, thereby jeopardizing the team. Elsewhere, Chuck worries that two flawless new operatives (Isaiah Mustafa, Stacy Keibler) will threaten his future as a spy; Morgan adjusts to a new roomie; and Ellie takes on potentially dangerous research. Robin Givens guest stars.
A whodunit case emerges when a spy is murdered in Team Bartowski's secret high-tech base. Elsewhere, Awesome embarks on a mission when Ellie takes on a potentially perilous hobby; Morgan is challenged when the Buy More crew battles Large Mart nemeses. Robin Givens guest stars.
When the CIA targets Vivian (Lauren Cohan) for death, Chuck tries to save her by forming a shadowy alliance with a dangerous enemy. Meanwhile, Sarah jolts Chuck with a relationship revelation; Ellie continues to dig into her father's past, but her mother (Linda Hamilton) may be trying to foil that effort. Timothy Dalton and Mekenna Melvin guest star.
The con is on when a swindler bilks Chuck and Sarah out of their wedding money. For help, they reach out to a master scam artist---Sarah's father (Gary Cole). Elsewhere, Morgan tries to push Casey into a face-to-face meeting with Alex's mother. Mekenna Melvin guest stars.
Chuck puts his spy endeavors on hold to delight in his bachelor party, but the big bash takes surprising turns because of some uninvited guests. Elsewhere, Ellie unearths game-changing information while snooping into her father's computer.
Chuck and Sarah prepare for their nuptials and tend to the pesky last details---one of which is scrambling to save Chuck's mother (Linda Hamilton) so she can attend the ceremony. Meanwhile, Morgan's duties as best man turn perilous when he tangles with Vivian; and Ellie cooks up ideas for the rehearsal dinner.
In the Season 4 finale, the team scrambles to soundly trounce Vivian Volkoff (Lauren Cohan) before she can destroy Chuck and Sarah's big wedding. Also in the mix: Alexei Volkoff (Timothy Dalton) and a thuggish agent (Richard Burgi).