Their spirit meets with Botan, the one in charge of taking the souls to the Reikai. There he knows Koennma, the prince of that world and he is in charge of of all the matters in his father's absence, as the boy's death it has been completely unexpected, Koenma offers to him a possibility to revive if it demonstrates that he can make good things in the earth.

Accompanied by Botan and a strange golden egg that contains his destiny, Yuuske helps several people and demonstrates to have a good heart. And it revives this way for his mother's happiness, of his friend Keiko and many more.

Koenma is impressed with its efforts and he offers him to work for him as a "detective" of the Reikai to take care that a balance exists between both Wolrds.(Makai & Reikai)

In their new lavor, Botan becomes his assistant and consultant.

Their first work consists on recovering three magic treasures that have been stolen by three Youkai or Demons, Yuusuke faces first with Gouki, which loves to eat the souls of the children.

Yuusuke decides to help him to get it without having to lose his life in the intent, grateful Kurama, returns him the favor and togetjer they will be able to conquer the third thief... Hiei. Hiei and Kurama, to repair their lack, are forced to collaborate with Yuusuke in their work and they finish being good friends.

The quartet is formed when a schoolmate of Yuusuke and old rival decides to unite to them: Kuwabara.

After receiving the training with the technique Rei-kou-hadou-ken (that consists in forming an energy sword), by Genkai, Yuusuke is prepared to face the different cases that would be assigned to theme.