The modern world has undergone drastic changes due to a sudden "dimension collapse": fictional cultures such as anime, myths and legends have been completely erased from human memory, and related traces have disappeared without a trace; at the same time, cracks in different dimensions frequently appear, and bloodthirsty "aliens" invade the earth through the cracks, putting human civilization in danger. In order to survive, human beings discovered that there are "dimensional spaces" hidden behind dimensional cracks - these spaces contain the residual power of fictional culture. Entering them and completing trials can obtain extraordinary abilities and techniques. This gave birth to a special group of "dimension walkers", and human civilization entered an era of struggle with dimensional power as the core.
