A strange, red circle appears on the neck of a man saved from the guillotine. What is its mysterious meaning? Tragically, it turns out to be something of a family curse, as each generation thereafter bears the same sign, which in turn leads to blackmail and murder.

A disfigured killer with glazed-over white eyes is doing the dirty work so that an insurance agent-doctor can get the victims' insurance money.

A wealthy businessman schemes to steal the valuable Crown Jewels from the heavily guarded Tower of London, but many tricky factors await, including a doppelgänger and a vessel escape on the Thames.