A British couple, Bob and Jill Lawrence, are on vacation in Switzerland with their teenage daughter, Betty. While attending a local festival, they befriend a Frenchman, Louis Bernard, who soon gets assassinated. With his dying breath, Bernard reveals to Bob critical information about an impending political assassination, entrusting him with the secret. The situation takes a dire turn when their daughter is kidnapped to ensure their silence, forcing Bob and Jill to abandon their holiday and return to London to investigate the conspiracy further and save their child.

Determined to rescue their daughter and prevent the assassination, Bob and Jill delve into a shadowy world of espionage and intrigue. They uncover a sinister plot involving an organized group capable of orchestrating high-profile assassinations. Bob tracks down clues while trying to stay one step ahead of the criminals. As they piece together Bernard's cryptic last words, their efforts lead them to a tense confrontation where the stakes couldn't be higher - the safety of their daughter and the prevention of a grave political crime.