In this comedy adventure period piece based on the story by Sir Arthur Conan Doyle, a boisterous French hussar and womanizer, Col. Etienne Girard (Peter McEnery), falls for a noblewoman during Napoleon’s (Eli Wallach) campaign in the Spanish peninsula. His affair with the enticing Countess Teresa (Claudia Cardinale), who's spying for the British against Napoleon, puts Girard at odds with his duties as she tries to enlist him for her cause.