At an all female high school, a senior of the radio club becomes fascinated with the club's newest member. As graduation nears and the summer heat rises, so does the sexual tension between the girls.

High school student Nanami lives in Tokyo, Japan. She waits for Halloween because she enjoys dressing up in costumes with her friends. One day, Nanami’s father tells her about a mysterious serial murder case that takes place year on Halloween. Her father works as the chief editor at an occult magazine. At first, Nanami doesn't care about the serial murders, but frightening incidents keep taking place around her.