Hydrosphere

The Colony on Rigel IV had been founded seven hundred years earlier but for the past six centuries, they had been forced to exist on the bottoms of the great oceans of the planet, kept there by the tremendously potent weapons of the alien star-race which had swept down out of space and wiped them off the land masses of the new world.

Kerrel Stevens found himself trapped in one of the Shells, unable to remember how he came to be there, aware only that for some strange reason, he held the secr...