General and Lady Fitzadam live at a remote army outpost in Scotland, their last assignment before the General retires. The General is sent abroad and in his absence, Lady Fitzadam decides to convert their spacious estate into a fishing resort for American tourists.

Gen. Hamish Fitzadam, due to retire from the military, needs money to buy the country cottage of his dreams. When the general leaves on an overseas mission, Lady Fitzadam devises a scheme to raise money by turning Glenmally, the general's Scottish Highland headquarters, into a luxurious salmon fishing resort for rich American tourists. The army staff agree to cooperate for a share of the profits, and Cpl. Sidney Green becomes hotel manager. The first guests, Americans Larry Hoffman and Sam Goulansky, settle down to enjoy the pleasures of the resort. While Hoffman fishes for salmon, Goulansky pursues Corporal Green's girl friend, the chambermaid. Hoffman soon becomes enamored of Lady Fitzadam, who poses as a widow. The general returns unexpectedly, but he is so outraged by the war minister's refusal to allow army trucks to move his furniture that he joins forces with his wife in the new business venture. They welcome a new guest, known as "the amorous Prawn" because of his notorious romances in the United States. Prawn arouses suspicion when he telephones the War Office, and it soon becomes apparent that he is the war minister. The hotelkeepers learn that the woman posing as Prawn's wife is a local barmaid, and in order to avoid a public scandal, Prawn agrees to allow the army trucks to move the General's furniture to his new cottage.