Chuck Bartowski is a socially awkward twenty-something who works as a computer expert at a local electronics retailer. On the night of his birthday party, Chuck receives an e-mail from his former Stanford University roommate, Bryce Larkin, who is now a "rogue" CIA agent. When he opens it, he unwittingly downloads an entire server of sensitive data, once only available to the Government of the United States, into his brain. Both the NSA and the CIA want the intelligence returned to them and dispatch agents of their own, Major John Casey and Sarah Walker, respectively, to retrieve the data. Because the disk with the government information breaks, Chuck experiences flashes of memory activated by certain subliminal triggers, he must use the knowledge he now possess to help the government thwart assassins and international terrorists, thereby upending his previously uneventful life. Chuck's decision to keep his newfound occupation a secret from his family and friends and to live his life as normally as possible forces Casey and Walker to establish an uneasy alliance (Walker poses as his girlfriend) with the shared goal of protecting Chuck at all costs.

(wikipedia.org)