Loose Lips follows the story of Selena Keller who has just completed a doctorate in Oriental Studies. Living in Manhattan, unemployed, and dismayed by her dull job prospects, on a whim she sends her resume to the CIA. Within weeks she is contacted by a recruiter, who asks her how she would feel about convincing another human being to commit treason.

Despite her checkered life history, she passes the background investigation, the polygraph, and a battery of bizarre CIA aptitude tests and begins duty as a Clandestine Service Trainee. Living undercover as a "government budget analyst", she is suddenly isolated from her family and her past. The loneliness and isolation of life undercover lead Selena into a romantic relationship with her classmate Stan, who cannot put a spy's habits aside, even in the bedroom. She learns that spies who fall in love with one another enter a wilderness of mirrors, where deception and betrayal are nothing less than professional obligations.