A wave of interplanetary aggression has covered the Universe. Unlimited power was concentrated in the hands of representatives of the Coalition of Human Supremacy. Believing themselves to be superior beings, they began to mercilessly destroy alien races. The few inhabitants of the planet Dimos who survived the bloody massacre became guinea pigs for people. Arriving on Dimos on an official mission, the writer Davis committed a terrible crime against the Coalition: he fell in love with a local woman, Lee, and condemned the genocide. To escape government agents, Davis and Lee decide on a deadly journey to the abandoned Zub fortress - the ancient refuge of the people of Dimos...