In the mid 1940’s, Quintessa Beaumont enlists in the Navy WAVES program (Women Accepted for Voluntary Emergency Service) to contribute to the US effort in World War II. Her assignment is to work at the Anti-Submarine Warfare Unit in Boston, with Lieutenant Dan Avery who is more eager to make admiral than work with her. As she works hard to prove herself, she finds strange things happing with a group of French ex-patriates and begins to wonder if there is a spy in their midst. Will Dan forgo his career advancement and help her in her research?