A spaceship arrives on Moonbase Alpha carrying a prisoner, whom Maya is astonished to learn is Dorzak, a survivor from her planet, Psychon. But can he, a man of peace, really be guilty of the crimes of violence for which he is being exiled?

Answering a distress signal, Commander Koenig is forced to crash-land his Eagle on Entra - moon of the planet Ellna - which turns out to be the planet's penal colony, and Koenig finds himself a prisoner of the beautiful Elizia and her equally beautiful prison guards.

The arrival of the Alphans on another planet seems to cause a change in its atmosphere, setting off pollution and poisoning of the water. They meet Zoran, the sole survivor of the last exploratory force, who tells them that the planet is controlled by an immortal being - with whom Koenig must parley if he and his crew are to leave the planet alive.