A spy after nuclear secrets poisons a scientist to obtain the information. But when scientist collapses on the street, he discreetly passes the chip on to Ellie. Then the spy goes after Ellie poisoning her. As team Chuck sets a trap for him, they all get exposed to the poison. Now they all need the cure. The poison compels them to tell the truth, which creates a dangerous situation for Chuck and Sarah.
Chuck meets a pretty girl with an unusual name, which causes an internal conflict. At the same time, his sister falls prey to someone the government seeks to apprehend.
- Chuck (Zachary Levi) attempts to save his sister after she is unknowingly poisoned by a nuclear arms dealer. Meanwhile a sandwich shop owner (Rachel Bilson) takes a liking to Chuck who then finds himself caught in the middle between her and Sarah (Yvonne Strahovski).