They call it Torus! It's a massive, towering, three hundred story alien structure mysteriously hovering above Earth, creating catastrophic earthquakes and global panic. David Keith is Mason Rand, a top-secret weapons specialist, whose job it is to unlock the secrets of the four-billion year old enigma. Solving the puzzle of the secret doorway, he enters a catacomb of power where men are vaporized, machines dominate, and the strange secrets of Earth's ancient history are revealed. Is it the doomsday bomb, an advanced alien life force, or the source of all power in the Universe? One thing's for sure, our only hope of survival is to take on the terror of Epoch.