When Chuck Bartowski (series star Zachary Levi) opens an e-mail subliminally encoded with government secrets, he unwittingly downloads an entire server of sensitive data into his brain. Now, the fate of the world lies in the unlikely hands of a guy who works at a Buy More Electronics store with his best buddy, Morgan Grimes (series star Joshua Gomez), and who lives with his ever-supportive sister, Ellie (series star Sarah Lancaster). Instead of fighting computer viruses, Chuck must now confront assassins and international terrorists. With the government's most precious secrets in Chuck's head, Major John Casey (series star Adam Baldwin) of the National Security Agency assumes the responsibility of protecting him. His partner is the CIA's top agent -- and Chuck's first date in years -- Sarah Walker (series star Yvonne Strahovski). They'll try to keep him safe when he trades his pocket protector for a bulletproof vest.

As Chuck continues to come to grips with his new spying life, tension builds between his recently appointed partners, and he must decide which of them to trust.

Chuck needs the help of Morgan and the Nerd Herd to prove that he is ready to become the store's assistant manager; Sara and John force Chuck to go under cover for his first real spy mission.

Chuck has to steal a million-dollar diamond from a Malibu mansion.

Chuck must decide if he should go against the U.S. government and his friends by helping a top Chinese spy with an unauthorised mission; Buy More forces Morgan into a sales competition that could cost him his job.

Chuck runs into a fellow agent who is living a similar life and must decide whether to turn the agent in to Sarah and Casey; Morgan's and Chuck's Halloweens differ.