By a coincidence, an engaging young cracksman (Robert Montgomery) chooses to open a safe and steal a diamond at the very moment a homicidal maniac is stabbing a policeman in the .
Though no mean cracksman ("I've got to get out of these wet clothes and into a dry martini"), he shunned the out--out gag, preferred to get his laughs while puttering among the .
A cocksure young cockney, Caine likes to picture himself as a consummate cracksman and his accomplice (Shirley MacLaine) as a dumb Dora who knows just enough to keep her mouth shut.