Yuyu Hakusho is a great japanese animated serie (anime). Is the history of a young boy, Yusuke Urameshi, a problematic guy who used to be a bad boy and he always was looking for fights. One day, he saved a boy from being run over by a car, but he died. Because he has this good action, in the spirit world, they decided to give him another chance, but from now on he must be a good boy and become a spirit realm detective and his job is to defeat the spirits that are causing troubles in the human world. In this task, he is guided by a beatiful girl named Botan. He is also helped by some friends like Keiko Yukimura (a girlfriend since they where very young), Kazuma Kuwabara (an old enemy who used to be always defeated by Yusuke), Hiei (a strong spirit, but with a dark personality), Kurama (or Shuichi Minamino, an antique spirit thief who now is a human), Genkai (a great fighter and she is Yusuke's teacher in martial arts), Koenma (he is the son of the ruler of the spirit realm) and Yukina (she is Hiei's sister).
Yusuke has to defeat this spirit to keep the peace in the earth, and he must to get stronger, so he goes to Genkai to learn more and he has a special power, the Rei Gun. The main menace is that the spirits wants to invade the human world, and he must stop them. This is why he participate in several tournaments and he has to face with his friends some very strong and interesting characters (Toguro brothers, Jin, Suzuki, Uraurashima, Touya, Shinobu Sensui, Raizen, Mukuro, Yomi). Each one of them leave to Yusuke Uramishi a teaching.
In the last part of the anime, he must to afront new enemies very strong. He met his father and inherit an entire realm. He must to keep the other world in balance, and he is always accompained by his friends.
Yuyu Hakusho is an excellent anime, with great fights, histories, enemies, adventures and romance (between Yusuke an Keiko). It's really an awesome anime! Go and see Yuyu Hakusho.