In 1943, the people of the isolated Scottish island of Todday are largely unaffected by wartime rationing, until their supply of whisky runs out. In the midst of this catastrophe, Sergeant Odd returns on leave to court Peggy Macroon, the daughter of the local shopkeeper. Meanwhile, her sister Catriona has just become engaged to meek schoolteacher George Campbell, although his stern, domineering mother refuses to give her approval. During a storm, the freighter S.S. Cabinet Minister runs aground near Todday and begins to sink. Two local inhabitants investigate and learn from its departing crew that the cargo consists of 50,000 cases of whisky. A battle of wits ensues between the stuffy English commander Wagget, who wants to confiscate the salvaged cargo, and the islanders.