Reuben Rosenthal is a crude man from South Africa who has done well in the diamond industry. He is extremely rich and not afraid to flaunt his diamonds.

Raffles determines to have some of Rosenthal's diamonds for himself, and stakes out Rosenthal's house in St. John's Wood using a variety of ingenious disguises.

He and Bunny break and enter, but all is not smooth sailing and Bunny has a particularly rough night.