A secret agent possesses a ring that makes him invisible for a short time, once every 10 hours. He is in pursuit of an evil criminal mastermind but, at the same time, must evade an enemy agent who also wants the ring.
Patrick O'Neal
Perry 'Matchless' Liston
Ira von Fürstenberg
Arabella
Donald Pleasence
Gregori Andreanu
Henry Silva
Hank Norris
Nicoletta Machiavelli
Tipsy
Howard St. John
General Shapiro
Sorrell Booke
Colonel Coolpepper
Tiziano Cortini
Hogdon (as Lewis Jordan)
