While vacationing in Morocco with their son Hank, American couple Dr. Ben McKenna and his wife Jo, a renowned singer, inadvertently become entangled in an international espionage plot. After a friendly encounter with a Frenchman named Louis Bernard, their new acquaintance is mysteriously murdered. With his dying breath, Bernard whispers a secret to Ben concerning a political assassination soon to take place in London. The couple is then thrust into a world of intrigue and suspense.

The McKennas' situation turns dire when Hank is kidnapped to ensure their silence. The couple is warned not to contact the authorities, forcing them to take matters into their own hands. They travel to London in a desperate race against time to prevent the assassination and to recover their son from the shadowy group responsible for his abduction. Hindered by their lack of knowledge about the conspirators and the intricacies of their plot, they must draw upon their own wits and courage to navigate through the layers of danger and deception.