Sumiko Harada, a poverty-stricken Japanese young woman and her father find a key and a letter on the body of a woman accidentally killed on a street in Tokyo. Sumiko's father uses the key to open a train-station locker where he finds a diary written by a sadistic serial killer who believes he is Akuma, the Japanese mythological devil who can bring misfortune to all who see him. Sumiko uses the information in the letter and the dead-woman's...