Slippery Rodney Haines runs a high-class gambling joint in Hampstead, while elsewhere in London Lamberti's Fair for the less-well-off is on its last legs. The only link between them seems to be Tommy Blyth, whose betting has put him in serious debt with Haines and who fancies Mary, the Lamberti's adopted daughter. In fact, there is a further unexpected link between the two worlds.