A wealthy lord dies and is entombed with a valuable deposit of jewels. Seven keys are required to unlock the tomb and get hold of the treasure. A mad doctor uses an iron maiden to systematically eliminate the heirs to the fortune.

When Lord Peter Wimsey marries Harriet Vane, a crime author, they both promise to give up crime for good. As a wedding present, Peter purchases the old house where Harriet grew up, but when they try to move in the previous owner is nowhere to be found, until they start to clean the house and find his body in the cellar...

An insane murderer is on the loose, and gunning for the men who put him away. Will Hay is on the list, and co-opts Claude Hulbert to try and stop him from meeting a grisly end.

Unsuccessful writer Aylmer Franklyn takes the chance to change identities after he discovers a corpse. However, he soon finds himself accused of the murder of a maid at a near-by boarding house.

In 1880, the criminal called The Wolf is responsible for a murderous rampage in France. When the Brisson Bank is robbed in Paris and the employee Michelle is murdered, the wealthy Chevalier Lucio del Gardo is the only chance to save the bank. Chevalier proposes to the owner M. de Brisson to deposit a large amount of gold, but in return he would like to marry his daughter Cecile. However, Cecile is in love with the efficient clerk Lucien Cortier that belongs to the lower classes and refuses the engagement. In order to get rid off the rival, Chevalier uses evidences to incriminate Lucien, manipulating the incompetent Parisian chief of police.