Back Cover:
Attack
The twin rings of Saturn were suddenly swarming with the robot ships of the deadly Sirian enemy.

The avowed antagonists of Earth, they had crossed 50 trillion miles of space to provoke a war which they knew they could not lose...for the awesome forces of earth dared not rally against the invaders.

Only Lucky Starr, of Earth's Council of Science, had a chance to avert the impending galactic holocaust. But one slip-up in his daring plan would mean certain death...and a place in history as Earth's most infamous traitor!