A traffic accident leaves 14-year-old independent street tough Yusuke Urameshi dead. His ghost watches the scene and recalls events leading up to his death. As he accepts his situation, Boton the Grim Reaper shows up, but her pink robes, baby blue hair and cheerfully chatty nature are not what Yusuke would've expected.
In Spirit World, Yusuke meets Koenma, the toddler-appearing son of King Yama, who presents Yusuke a chance for coming back to life through a spirit egg that will feed off his soul's energy. If Yusuke's energy is good, a spirit beast will hatch that will guide him; if not good, a monster will emerge to devour him. In the meantime Yusuke struggles to tell those closest to him in the living world not to cremate his body.
While waiting for his spirit egg to hatch, Yusuke's estimation of Kazuma Kuwabara rises stemming from the rare opportunity to observe his goofy rival dealing with two teacher going out of their way to hurt him, expel him and ruin a friend's life.
Sayaka the spirit investigator checks up on Yusuke's progress, particularly looking into Yusuke's relationship with Keiko, which seems entirely one-sided. An emergency arises putting Keiko's life and Yusuke's chance for a return in jeopardy, and Yusuke must make a consequential decision.
To reclaim his body, Yusuke must enter the dreams of the three people who want him back the most and convince at least one of them to kiss him on the lips before tomorrow at midnight or else he'll remain a spirit hovering over his comatose body for the next fifty-two years.
Yusuke gets his first assignment as Spirit Detective: Three criminals have stolen dark artifacts from King Yama's vaults in Spirit World. They must be caught and the items returned - a tall order, especially for an untested, first-time Spirit Detective like Yusuke.
Hiei, the last and feistiest of the three artifact thieves, attempts to weaken Yusuke by first attacking Keiko. He starts transforming her into a demon but finds that attacking Yusuke's friends only magnifies, not weakens, Yusuke's fighting abilities, making their confrontation more interesting. Aid later comes to Yusuke from an unexpected source.
Master Genkai is retiring and looking for one last apprentice to whom to pass along her special psychic fighting powers. Koenma wants Yusuke to enter her contest for that apprenticeship, not only to gain those special powers but to discover a homicidal master criminal named Rando who's surely to be one of the contestants as well. Arriving for the qualification tests, Yusuke meets a familiar acquaintance.
Genkai's final test is a tournament between the eight finalists, fought one-on-one in her pitch black dojo until opponents are either dead or incapacitated. All the while, Yusuke wonders which one may be the homicidal Rando in disguise.
Kuwabara and Shorin face-off in the semi-finals of Genkai's tournament, which goes directly into the final match with Yusuke; however, when all seems said and done and a winner about to be declared, Rando the human-hunter finally appears, portending dire consequences for all those still alive.