The story is set one hundred years into the future. Forty years have passed since the discovery of “parallel universes (multi-universe).” And globalization, as well as science and technology, continue to advance. The protagonist, Tomoe, makes a living out of chasing criminals as a bounty hunter. But due to information from Kira Seishiro —an administration bureau member of public security transfer— in order to save her endangered self on another Earth, she departs on a journey throughout the multi-universe.