Yu Yu Hakusho (Japanese: 幽☆遊☆白書 Hepburn: Yū Yū Hakusho) is a Japanese manga series written and illustrated by Yoshihiro Togashi. An anime adaptation consisting of 112 television episodes was directed by Noriyuki Abe and co-produced by Fuji Television, Yomiko Advertising, and Studio Pierrot. The television series originally aired on Japan’s Fuji TV network from October 10, 1992 to December 17, 1994. It was later licensed in North America by Funimation in 2001, where it aired on popular Cartoon Network blocks including Adult Swim and later Toonami. The television series has also been broadcast in various other countries around the world.
Yu Yu Hakusho follows Yusuke Urameshi, a 14-year-old street-brawling delinquent who is hit by a car and killed in an attempt to save a young boy. His ghost is greeted by Botan, a woman who pilots the River Styx and ferries souls to the “Underworld”. Koenma, son of the Underworld’s ruler King Enma, offers Yusuke a chance to return to his body through a series of tests. Yusuke succeeds with the help of his friends Keiko Yukimura and Kazuma Kuwabara. After returning to life, Koenma grants Yusuke the title of “Underworld Detective” (lit. “Spirit World Detective”), charging him with investigating supernatural activity within the Human World. Soon Yusuke is off on his first case, retrieving three treasures stolen from the Underworld by a gang of demons: Hiei, Kurama and Goki. Yusuke collects the three treasures with the aid of his new technique, the “Rei Gun”, a shot of aura or “Spirit Energy” fired mentally from his index finger. He then travels to the mountains in search of the martial arts master Genkai. Yusuke uses Genkai’s competition as a cover to search for Rando, a demon who steals the techniques of martial arts masters and kills them. Yusuke defeats Rando and trains with Genkai for several months, gaining more mastery over his aura. Yusuke is then sent to Maze Castle in the Demon Plane, a third world occupied solely by demons, where Kuwabara and the newly reformed Kurama and Hiei assist him in defeating the Four Beasts, a quartet of demons attempting to blackmail Koenma into removing the barrier keeping them out of the human world.
Yusuke’s next case sends him on a rescue mission, where he meets Toguro, a human turned into a demon. Toguro invites Yusuke to the Dark Tournament, an event put on by corrupt, rich humans. Team Urameshi, consisting of Yusuke, Kuwabara, Kurama, Hiei and a disguised Genkai, traverse through the strenuous early rounds to face Team Toguro in the finals and win the tournament. Team Toguro’s owner, Sakyo, destroys the tournament arena, killing himself in the process.
Yusuke returns home, but is challenged to a fight by three teenagers possessing superhuman powers and who end up taking the detective hostage. Kuwabara and the others rescue him and learn that the whole scenario was a test put on by Genkai. It is revealed that Shinobu Sensui, Yusuke’s predecessor as Underworld Detective, has recruited six other powerful beings to help him take over where Sakyo left off, opening a hole to the Demon Plane in order to cause genocide of the human race. Yusuke and his friends defeat Sensui’s associates one-by-one, culminating in a final battle between the two detectives. Sensui kills Yusuke then retreats into the newly opened portal to the Demon Plane. Yusuke is reborn as a partial demon, discovering that his ancestor passed down a recessive gene that would hide until an heir with sufficient power surfaced, when his demonic lineage would be revealed. Yusuke travels to the Demon Plane and defeats Sensui with the aid of the spirit of his ancestor who takes control of Yusuke’s body to finish the fight.
As they return to the human world, Yusuke is stripped of his detective title as King Enma orders he be captured and executed. Yusuke accepts an offer by Raizen’s followers to return to the Demon Plane. Raizen is on the brink of dying of starvation and desires a successor , a death that would topple the delicate political balance of the three ruling powers of the Demon Plane. Hiei and Kurama are summoned by the other two rulers, Mukuro and Yomi, to prepare for an inevitable war. The three protagonists train in the realm for one year, during which time Raizen dies and Yusuke inherits his territory. Yusuke takes initiative and proposes a fighting tournament to name the true ruler of the Demon Plane, which is agreed upon by Mukuro and Yomi. During the tournament, Yusuke and Yomi meet where Yusuke is defeated and knocked unconscious. Yusuke awakens days later to find that the tournament has ended and that a similar competition is to be held every so often to determine the Demon Plane’s ruler. Yusuke eventually returns to the human world after several years to be with Keiko.