Olga is a middle-aged librarian who lives with her loving husband and young son in Budapest, sometimes visiting her elderly mother living in Germany. One day, the state police show up and suspect her of espionage, and she learns that her friend she met there is a German spy who is very curious about her husband's work. In exchange for impunity, they offer her to work for them, thus capturing the German secret service. Olga agrees to a double game full of dangers.