After a series of misunderstandings, the head of an aerospace research laboratory begins to suspect that his new girlfriend is a Russian spy.

Jennifer Nelson and Bruce Templeton meet when Bruce reels in her mermaid suit, leaving her bottomless in the waters off Catalina Island. She later discovers that Bruce is the big boss at her work (a research lab). Bruce hires Jennifer to be his biographer--only to try to win her affections. However, there's a problem: Bruce's friend General Wallace Bleeker believes that Jennifer is a Russian spy, and he has her placed under surveillance. When Jennifer catches on...Watch Out.—Kelly

While not acting as a swimming mermaid for her father's Catalina-based glass-bottom-tour-boat business, widowed Jenny Nelson works in the PR department of NASA, primarily acting as a tour guide. Feeling like no man can replace her husband, she spends her personal time looking after her menagerie of pets or taking night classes. Bruce Templeton, a research scientist on contract to NASA, enters her life in a romantic sense, despite their auspicious and antagonistic initial meeting. Bruce does anything he can to infiltrate Jenny's life, and soon she believes she's falling in love with him. Bruce's true work for NASA is on a gravity project called GISMO, the secret equation on which enemy regimes would love to get their hands. CIA and NASA officials begin to suspect Jenny's a spy working for the Soviets, something which Bruce does not believe. The true spies working for the Soviets also begin to believe Jenny's a spy working for another enemy regime. Jenny and Bruce's relationship is threatened by these suspicions, and further threatened if Jenny would ever learn of the deceptions Bruce used to enter her life.—Huggo