A family of well-to-do crooks who are shocked when the son, an excellent forger, quits the fold to go straight. The reason is not long hidden: he has met a girl. He takes a job in a bank (his forged references are excellent). The family makes every effort to get him back into his ancestral profession, to no avail, until it is discovered that his fiancée, the daughter of a Scotland Yard inspector, is a first-class safe-breaker. The white sheep is happy to re-enter the fold, and the family welcomes their talented new daughter-in-law. Half the fun of the play is the way in which the members of the family rationalize their trade on the basis of free enterprise economics.