Back of cover
An outlying system of the Terra Federation has set up an advanced anti-matter conversion plant on a centrally positioned asteroid to supply the local colonists with energy. A surprise attack by alien forces the has successfully overcome the asteroid's defences and the aliens are now threatening to sel-destruct the power plant unless the colonists offer an unconditional surrender. The self-destruction process would effectively turn the power plant into a massive black hole that would wipe out the entire planetary system along with a number of nearby stars. Unconditional surrender offers an equally horrific prospect. Your mission is to infiltrate the enemy position and disable the anti-matter plant before the aliens achoeve CRITICAL MASS.