Scotland Yard investigates a series of murders where the victims have died by snake venom poisoning.

Scotland Yard must discover why people are being murdered by a monstrous dog at Blackwood Castle.

This time Fu Manchu and his army of henchmen are kidnaping the daughters of prominent scientists and taking them to his remote island headquarters. Instead of asking for ransom, Fu demands that the fathers help him to build a death ray, which he intends to use to take over the world. But Fu's archenemy, Nayland Smith of Scotland Yard, is determined not to let that happen.

The sister of a famous, but as yet uncaught, criminal named "The Hexer" is murdered. Inspector Higgins of Scotland Yard believes that "The Hexer" will surface to take his revenge on his sister's killers, and plans to set a trap to finally capture him. However, soon bodies start piling up, and it looks as if "The Hexer" may get away yet again.

Arthur Milton aka Der Hexer (The Magician/Ringer) must return to London after his calling card was left at the scene of a murder he did not commit.

When a wealthy man dies, his avaricious relatives look forward to inheriting all his money. However, he leaves a provision in his will that they all must spend a week together in his castle before they will be able to inherit anything. At the castle (which is cut off from the outside world), the relatives soon begin to be killed off one by one, each strangled with an Indian scarf.

A circus becomes the location for stolen loot and murder.

A rich man bequeaths seven keys to seven of his friends, but only one will unlock the door to untold wealth.

A maniac is loose in London, decapitating his victims and sending the heads to Scotland Yard.

A former district officer is assigned to work on a team of diamond prospectors, who are busy double crossing each other until they are blown up having found bullion.