Cherry Winters runs a chain of sex shops. One night, she is expecting the return of her lover, Bill but it is not Bill who creeps into her dark flat. Martin has mistaken it for the one opposite, which is inhabited by his own fiancee, Helen. Unfortunately not only does he mistake the flat, but also the bed. Unsuspecting Cherry thinks it is Bill and welcomes him with open arms until they are later suprised by Bill himself! From this auspicious beginnng flows a flood of complications!