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.

Chuck and Sarah investigate when they suspect that Casey is carrying out private missions. Meanwhile, Chuck fears that the CIA's seemingly perfect new operatives will render him obsolete. Elsewhere, Morgan settles in with a new roommate, and Awesome panics when Ellie embarks on a potentially dangerous line of research.