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.
The eternal Hercules in this film has gone way beyond his usual time and place in ancient Greece and is now helping Poland free itself of Mongol invaders in the 12th century. Mark Forest is the star of this peplum epic, Hercules Against The Barbarians.