A young, English, ne'er-do-well who goes to stay with his sister and her wealthy fiancé/benefactor in 1930's Germany, just before the rise of the Nazi party.

When the detective in charge of investigating a series of bank robberies starts to get too close to the culprits, they set up a blackmail scheme to warn him off. But when the crooks begin to fall out with each other, the police learn the truth.