Over the course of 3,000 years in the cosmic calendar, humanbeings have established prosperous civilizations in everycorner of the universe. However, a perplexing mystery hasalways haunted the human mind: Why, in this universe, arethere no other traces of intelligent civilizations apart fromhuman beings themselves?
A chance exploration led humans to discover that there was acosmic wall at the edge of the universe, which was like amysterious gateway leading to another unknown world. Whenhumans crossed the tunnel of the cosmic wall, they suddenlyrealized that the universe was not unique, and there werenumerous diverse alien creatures in another universe.      However, this discovery did not bring new opportunities but adevastating crisis. Alien creatures from across the universeflooded into this universe like a tide. Their power and formsexceeded human imagination. Although humans already had ahighly developed civilization and technological level reached anastonishing height, in the face of these aliens, technologyseemed so powerless...