Unidentified Flying Objects streak in from the lunar horizon and the savage noses of SHADO interceptors swing eagerly towards their flight path.

Any error now spelt death to a sleeping Earth.

Suddenly the link with Supreme Headquarters, Alien Defence Organisation, slides away into a colour-splashed infinity — is Moonbase at the mercy of her enemies?

MEET THE SPACE GUERILLAS

Code name SHADO. The most secret, sophisticated — and important — group on Earth. Only they know that mankind is under attack by a hostile intelligence from outer space.

A silent, invisible invasion by deadly aliens, bent on conquest and extermination. And SHADO's mission is to seek, find and destroy the un-humans.

Were the aliens un-human invaders or new friends? Should humanity make welcome or war? SHADO couldn't afford to guess wrong — the stakes were the survival of the human race.