A diamond advocate is attempting to steal a collection of diamonds, yet troubles arise when he realizes that he is not the only one after the diamonds.
Two out-of-work actors — the anxious, luckless Marwood and his acerbic, alcoholic friend, Withnail — spend their days drifting between their squalid flat, the unemployment office and the pub. When they take a holiday “by mistake” at the country house of Withnail’s flamboyantly gay uncle, Monty, they encounter the unpleasant side of the English countryside: tedium, terrifying locals and torrential rain.