森羅学園中等部に通う少年・小山田まん太は、ある日の帰宅途中、墓場で幽霊と戯れる少年と出会う。少年の名は麻倉葉。彼は霊と様々な交流ができる者、シャーマンと呼ばれる者達の一人だった。彼は500年に一度行われるシャーマン同士の戦い「シャーマンファイト」に参加するために上京してきていた。シャーマンファイト、それは全世界のシャーマンを統べる「シャーマンキング」を決める戦いである。葉と友人になったまん太は、彼を通じて様々なシャーマンたちと出会い、その戦いを目撃していく。
On a starry night, middle-schooler Manta meets Yoh Asakura, a young shaman who has the ability to talk to spirits, and also has the ability to let them possess him to use their powers. Yoh has a heavy duty on his shoulders: he must become the Shaman King by winning the Shaman Fight, a tournament between shamans that happens only once every 500 years. Joined by his spirit medium fiancée Anna Kyōyama, his personal samurai spirit Amidamaru, and his other friends, Yoh must also face a larger evil: Hao, a powerful man who aims to create a new world with only shamans by becoming the Shaman King himself.