The ultimate criminal mastermind is on the loose in this dynamite Euro-crime triple feature! The Return of Dr. Mabuse: The most fiendish villian of all time plans an alliance with the Chicago crime syndicate. A series of crimes and killings sets Inspector Lohman (Goldfinger"s Gert Frobe) and FBI agent Joe Como (Lex Barker) on a trail of danger where no one is whom they appear to be! The Invisible Dr. Mabuse: A beautiful dancer is terrorized by an invisible man, and FBI agent Joe Como (Lex Barker again!) is out to catch the killer of a fellow agent. At the heart of the mystery is "Operation X," an invention capable of giving unlimited power to its owner. Is Dr. Mabuse behind the danger, or is the invisible being something even more sinister? Find out in this thrilling mixture of mystery, intrigue and a dash of Phantom of the Opera. The Death Ray Mirror of Dr. Mabuse: The demon of crime is back, reaching out to steal a new device-- a death ray weapon enabling Dr. Mabuse to wreak new havoc upon the world. British agent Floyd Anders is sent to the isle of Malta to protect the weapon"s inventor, Professor Larson, and must race against time to discover which of the various suspects is really the power-mad Dr. Mabuse.