The first season of Chuck introduced the series' main characters and established the general plot of the title character, Chuck Bartowski, having to adapt to his new life as a spy after the only remaining copy of the U.S. government's spy secrets are embedded into his brain. He is forced to juggle his responsibilities as a spy and the supervisor of a technical support team, called the "Nerd Herd", at his local Buy More store. Having become the most important asset of the U.S. government, Chuck is under the constant surveillance of his CIA handler, Sarah Walker, and NSA agent John Casey, who remind him that he cannot reveal his spy life to his sister Ellie, nor his best friend Morgan Grimes.

The second season continues to focus on Chuck's constant struggle to keep his spy life and real life apart as he becomes more accustomed to being a spy. More background on the Intersect project is revealed. Fulcrum, a hostile espionage organization that covets the Intersect, is featured more heavily as the season's main antagonist. Chuck and Sarah continue to grow closer, complicating their asset-handler relationship.

In season three, Chuck finally has the potential to become a real agent. There's just one problem — his emotions. Can Chuck keep them in check as he assumes his new role as the Intersect 2.0? His handlers, Sarah Walker and John Casey, will still be there to protect him, but they also must help him become the agent he is destined to be.

With Chuck's new Intersect abilities — resulting from a data upgrade and some actual spy training — he is now fully equipped with deadly fighting skills and ready to face the Ring. Can Chuck truly become the spy he longs to be, or will his emotions continue to get in the way?

The fifth and final season continues from the cliffhanger ending of the fourth season finale. With the help of his unlikely team and unorthodox techniques, Chuck is ready to take Operation Bartowski freelance. Chuck’s spy abilities will be put to a new test when he and his team must save mankind without the help of the CIA. Instead, they'll use the cover of the Buy More electronics store to fund their own operations, leading to new missions, new stakes and new obstacles.