Fourteen-year-old thug Yuusuke Urameshi spends his days skipping school and causing trouble for the adults in his life. Yuusuke regularly engages in street brawls against rival Kazuma Kuwabara and ridicules his childhood friend Keiko Yukimura. Filled with self-loathing and the burden of an alcoholic mother, Yuusuke sacrifices it all in a split-second decision—he tackles a small child out of the way of an oncoming car, losing his life in the process.

Spirit guide Botan intervenes, allowing Yuusuke to see how the people in his life react to his death; he is moved by the emotional ruin his loss causes his mother, Keiko, and even Kuwabara. Additionally, due to his death's heroic nature, he receives an opportunity to return to life from the Spirit World ruler's son, Koenma.

Koenma hires Yuusuke as a "Spirit Detective" and tasks him with solving a series of increasingly challenging paranormal mysteries. Battling and befriending demons such as the beautiful Kurama and hostile Hiei, Yuusuke further develops and utilizes his skills as a fighter. But as dark forces move in the Underworld, Yuusuke struggles alongside his companions to defend everything he took for granted.