Humanity is waging a war against the Rull, alien to humanity and compassion, destroying intelligent life on any planet available to them. Their race is so alien and paranoid that they must come from another galaxy. Their true appearance is something like a dark, large worm with many different appendages. But they can take on any form. Only the Ezvals, who have telepathy, but hide their intelligence from representatives of other races, can help in this protracted confrontation...