2348. Humans emigrate easily from one planet to another and peaceful contact is made with many races of alien beings. Yet problems arise with certain races, so the Earth Federation beginsresearching a plasma-power weaponto protect Earth. The top physicist for the Earth Federation, Dr. Edward Bilstein, uncovers the secret to humanity's "sixth sense": a technique for capturing the energy of the human mind. The plasma weapon is built, usingmental power as its basis. Bilsteinreaches fame and fortune for the invention, but is quickly exiled when it is revealed actual human bodies were used in his experiments. Bilstein is placed in a floating prison cell that orbits the planet Zeta, and developmentof the plasma weaponis suspended.

Word of the Earth's possession of a super-weapon spreads throughout the heavens, and the solar system becomes a peaceful place. The name Edward Bilstein is completely forgotten. Until four years later. . .

A report from Zeta states that a Federation army base was attacked and immediately destroyed by a small group of rebels calling themselves the "Fourth Empire." Several other similar reports come out of other nearby planets. The pattern of attacks leads back to Earth, sothe Federation believes Bilstein is coming back for revenge.

A man as dangerous as Edward Bilstein can be stopped in only one way. He must be attacked before he reaches Earth. The Federation Army hastily organizes people who can utilize the Plasma weapons against their own creato r andbattle the "Fourth Empire." All Earth's hopes rest in the project code named "Star Gladiator."