To cover the gambling debts of his daughter Kitty Imber, the widowed Lord Theign is planning to sell his beautiful painting Duchess of Waterbridge by Sir Joshua Reynolds to American billionaire Breckenridge Bender. Hugh Crimble, a young art critic, argues against the sale, saying that Britain's art treasures should stay in the country. He is supported by Theign's perceptive daughter, Lady Grace. When the newspapers get wind of the potential sale of the Reynolds, they raise a patriotic outcry, which delights Bender.