While a people of alien warriors who have lost their original planet, the Sylvrides, plot the invasion of the Earth and the annihilation of humanity, the Earthlings live in opulence, drowned in unconsciousness and futility, blind to the real threats that lie ahead of them. For a few months before the beginning of the story, a mysterious dark sphere, covered with glyphs, has crashed on Earth. A clear sign, which remains invisible to the population. The brave men and women have all gone into space to try to cut the grass under the feet of the potential invaders. But none of them has seen the coming of the Mazones and now the Earth finds itself defenceless...or almost.