Employed as a servant in the household of Sir Thomas Booby (Peter Bull), the pure-hearted Joseph is in love with Fanny Goodwill (Natalie Ogle), one of the housemaids. But Joseph is plagued by the unwanted attentions of the copiously endowed former actress Lady Booby (Ann-Margret), who becomes even more aggressive after the death of her husband. When he refuses the advances of his employer, Joseph is beaten by her minions and left for dead before being rescued by a passing coach. He finally reunites with his friend Parson Adams (Michael Hordern), who has just saved Fanny from rape. As the farcical plot accelerates, the virtuous trio get into a surprising number of scrapes, narrowly avoid being jailed for crimes they didn't commit, and are unwittingly lured to a Black Mass organized by an evil nobleman. Meanwhile, Lady Booby, scheming to ensure that the marriage of the young couple never occurs, has Fanny framed and arrested for robbery.