Sensational film about the Spanish War of Independence (1810). After Napoleon's invasion of Spain, a group of guerillas (led by Frank Sinatra) attempt to transport what was in those days the biggest cannon in the world, across Spain to Avila, where they intend to counterattack against the French army headquartered there. But a British Navy captain (Cary Grant) is trying to locate the cannon for the British to use against Napoleon. Adding romance to the plot is Sophia Loren, who becomes the object of Grant's and Sinatra's affections.