The story arc takes place immediately following the defeat of Shinobu Sensui. Yusuke Urameshi has fallen into a malaise, due to a demon's interference in his fight with Sensui. Not knowing who to turn to, he travels to Genkai, in an attempt to figure out what to do next. After subjecting him to her trademark sardonic wit, Genkai suggests visiting the original Spirit Detective for Earth, Kuroko Sanada, for advice. Yusuke does so, only to have the visit interrupted by three messengers from Demon World, who claim to have all the answers he's been seeking. They inform him that the demon who possessed him during his fight with the renegade spirit detective was, in actuality, his ancestral Demon father, Raizen, one of the three kings of Demon World, who is now currently on the cusp of death, due