In a world where memories are stored on chips separate from the body, physical death no longer equates to the death of the soul. Memories can be viewed, altered, and transferred between bodies. The wealthy use these memory chips to achieve eternal life in carefully selected bodies, whereas for the poor, selling their bodies and preserving their souls in chips often becomes the only means of survival. An electrolytic cloud in the sky acts as a barrier between the heavens of the fortunate and the underworld of the destitute, rendering this social division impregnable. One day, a man named Kaiba wakes up in an empty room with no memories, a mysterious hole in his chest, and a locket containing a picture of an unknown woman. After escaping an attack and stumbling upon a decrepit village of underworld residents, he begins an adventure across the different planets of this strange universe to learn more about his own identity and the woman he once knew. Through a journey of self-discovery and acceptance, Kaiba weaves together tales of souls and spirits and explores the importance of memories.