When American millionaire Charles Delacro (Robert Mitchum) stumbles into the private quarters of Victor (Cary Grant) and Hilary (Deborah Kerr), an English aristocratic couple who allow public tours through their stately mansion, he brings a whirlwind of trouble with him. Hilary's dissatisfaction with her staid life plus verbal sparring with Charles about Anglo-American differences spark a romance between the two, easily perceived by Hilary's husband, Victor. When Hilary goes to London to meet Charles secretly, an old flame of Victor's visits to give him advice on his disintegrating marriage and to perhaps seduce him too. Victor's solution' Invite his wife's lover up for the weekend to engage in some fishing and a duel. Woven together with a wide streak of humor is a wonderful, surprisingly rich and blunt scrutiny of marital troubles and endurance.