While coping with the realization that Sarah still has feelings for Bryce, Chuck must assume his toughest cover yet by going on a mission as Sarah's husband. The team must foil the plot of a politically connected counterfeiter, who may be endangering the lives of Anna, Morgan and Anna's parents. Both Morgan and Anna also find themselves in the cross hairs.

Chuck's latest mission has him raiding a Malibu mansion to grab a million dollar diamond being used to fund terrorism. Tagging along is an attractive but less-than-trustworthy DEA agent.

Chuck gets jealous when Sarah has to seduce a Fulcrum agent. Meanwhile, Jeff and Lester start looking for the "Buy More Babe" as a way of finding a new employee.

As Chuck is beginning to adapt to his new life as a spy, a doctor who could possibly "cure" Chuck is murdered. Chuck then begins a high-speed fight for his life, all while trying to decide which of his two new colleagues might be out to get him. Meanwhile, Chuck's sister Ellie invites Sarah to dinner to meet the family.

When Chuck go undercover in Milan, Chuck realizes the "Achilles' Heel" in their relationship, but must set personal issues aside for the mission. Meanwhile, Morgan recognizes a fatal flaw that compromises the new Buy More. Elsewhere, Casey struggles to put down roots in Burbank.

Chuck Bartowski is an average computer geek until files of government secrets are downloaded into his brain. He is soon scouted by the CIA and NSA to act in place of their computer.

With the help of his old nemesis Alexei Volkoff, Chuck and the team hunt down a deadly weapon, The Norseman. In a pre-wedding surprise, Sarah springs a pre-nup on Chuck.

Chuck turns to Verbanski for help tracking a computer virus. Lester and Jeff's relationship is complicated by a new Buy More employee.

Chuck needs the help of Morgan and the Nerd Herd to prove that he is ready to become the store's assistant manager. Sarah and John assign Chuck his first undercover spy mission to foil a terrorism plot.

After his intuition is wrong while working on a stakeout, Chuck feels morally obligated to make things right, even when both Sarah and Casey refuse to help with Chuck's new mission. Meanwhile, Morgan has to participate in a sales competition that could decide his fate at Buy More.

In this Halloween episode Chuck meets a Federal agent just like him: A computer whiz whose brain is important to national security. However, Chuck soon has a personal dilemma arise when he has to decide whether or not to turn the man over to Sarah and Casey or to help him escape his handlers.

Returning to Stanford, the University that expelled him, Chuck has to help a former professor who is a government agent being hunted for a sensitive top-secret file he has in his possession. At the same time, Chuck learns much about himself and about the death of his friend Bryce Larkin.

The episode begins with a flashback to the year 2004, where John Casey is involved with a female Russian named Ilsa, who claims she is a photo journalist. Later, in present day, Ilsa returns with a fiancé, named Victor Federov. Things get complicated when it is revealed that Ilsa is a French spy.

Chuck goes undercover at Sarah's 10-year High School reunion, where they meet the girl that tortured Sarah back in the old days.

Chuck and Sarah try to become better communicators as they join Ellie and Awesome on a trip to Costa Gravas; a forbidden romance may put Morgan at odds with Col. John Casey.

Chuck, Sarah, Casey and Morgan must stop Dr.Stanley (Robert Englund) from releasing a toxin that induces nightmares... Chuck's mother's allegiances are questioned; Lester and Jeff celebrate Halloween at the Buy More.

Chuck, Sarah, Casey and Morgan venture into the jungles of Southeast Asia when The Belgian attempts to unravel the secrets of the Intersect. Meanwhile, Captain Awesome and Ellie try to decipher a secret left behind by her father.

Casey, Chuck and Sarah are sent to Morocco to rescue Roan Montgomery. Morgan plans to meet Alex's mother and Mary spends some time with her family.

Valentine's Day is interrupted when Chuck and the team are sent on a mission to England to protect a reclusive young heiress, Vivian McArthur. Meanwhile, Casey gets an offer from the mysterious Jane Bentley. Back at home, Ellie and Awesome find an unlikely solution to a parenting problem, as Morgan ponders a big move.

As the team takes on a missing persons case, Chuck and company struggle to establish themselves as Carmichael Industries in the face of a rival security firm led by the tough and efficient Gertrude Verbanski. Meanwhile, Morgan continues to adjust to the Intersect while Chuck adjusts to being his handler. Also, the Buy More finds an unlikely spokesperson to help drum up business.

Chuck and Sarah track an assassin who is trying to eliminate the new intersect. Morgan tries to adjust to having the intersect. Jeff exposes a new side of himself.

Chuck needs to go undercover to seduce a woman named Sasha Banachek, so an old school spy named Roan Montgomery is assigned as his mentor. Meanwhile, Captain Awesome finds himself in need of some relationship advice, and and turns to Morgan, and Lester faces his first problems as assistant manager.

The team is assigned to survey the Global Launch Agency, when intel shows that someone might penetrate their security. During the surveillance someone intrudes the lab who turns out to be Casey's former sensei Ty Bennett. Meanwhile, Captain Awesome's perfect parents decide to pay Devon and Ellie a surprise visit to help them plan the wedding, and Emmett Milbarge introduces an "Employee of the Month" contest to the Buy More, but the employees start their own contest instead.

Chuck and Sarah's romantic mission is canceled with the arrival of Hugo Panzer and Heather Chandler. But Chuck grows more interested when the manipulative Heather claims to know a secret about his mom. Meanwhile, as Morgan prepares the Buy More for a huge video game release, he gets a surprise from Big Mike.

Chuck surprises Sarah with her old spy team, The C.A.T. Squad, leading to a mission in Rio. As The C.A.T. Squad works to settle a score with Augusto Gaez, old secrets and grudges come to light. Back at the Buy More, Morgan fends off the advances of Carina, a former flame and frisky member of The C.A.T Squad.