An ex-convict who's built a respectable post-prison life for himself as an engineer discovers that a past is a hard thing to shake. When old "friends" contact the former prisoner, it's not long before the gone-straight baddie finds himself being blackmailed into taking part in a major jewelry theft.

An elderly spinster plans a perfect robbery in Soho.

Insurance salesman Tom and his wife Jenny are struggling through the first years of marriage in a modest flat, on Tom's even more modest salary. By contrast Drew, Tom's old army pal, is a footloose bachelor currently running a car-hire firm owned by his rich uncle, who lives in Canada. Since Drew's uncle makes it clear that his nephew will only inherit the business when he's a respectable married man, his upcoming visit throws Drew into a panic. Having taken a fancy to the vivacious Jenny, Drew persuades her to masquerade as his wife – an arrangement that leads the trio into some highly complicated situations!