幼い頃に初恋の少女と大切な約束を交わした天川春人。しかしそれは、少女の失踪と自身の身に起こった事故により、果たされることはなかった。そして【天川春人】だった青年は、異世界のスラムで生きる孤児の少年【リオ】へと転生し――!?　前世と現世が交錯する大人気異世界転生ファンタジー、待望の新コミカライズ！

Amakawa Haruto is a young man who died before reuniting with his childhood friend who disappeared five years ago. Rio is a boy living in the slums who wants revenge for his mother who was murdered in front of him when he was five years old.

Earth and another world. Two people with completely different backgrounds and values. For some reason, the memories and personality of Haruto who should’ve died is resurrected in Rio’s body. As the two are confused over their memories and personalities fusing together, Rio (Haruto) decides to live in this new world.

Along with Haruto’s memories, Rio awakens an unknown special power, and it seems that if he uses it well, he can live a better life. But before that, Rio encountered a kidnapping that turns out to involve two princesses of the Bertram Kingdom that he lives in.