The Diclonius, a mutated homo sapien that is said to be selected by God and will eventually become the destruction of mankind, possesses two horns in their heads, and has a "sixth sense" which gives it telekinetic abilities. Due to this dangerous power, they have been captured and isolated in laboratories by the government. Lucy, a young and psychotic Diclonius, manages to break free of her confines and brutally murder most of the guards in the laboratory, only to get shot in the head as she makes her escape. She survives and manages to drift along to a beach, where two teenagers named Kouta and Yuka discovers her. Having lost her memories, she was named after the only thing that she can now say, "Nyuu," and the two allow her to stay at Kouta's home. However, it appears that the evil "Lucy" is not dead just yet...

Green City Kazamatsuri is a city built on the ideal of a harmonious relationship between civilization and environment.. However, the peaceful Kazamatsuri will soon be faced with its annual commotion, the Harvest Festa at the turn of the year. It's an event that is much like a massive school festival, and Tennoji Kotaro decides to head out to research topics for his articles. It's an easy decision for him, because the town is filled with rumors about unidentified creature sightings and various other occult occurrences. At the same time, strange things start happening to Kotaro himself.

Four married couples try to save their marriages by entering into a social experiment. During this experiment, the four couples switch spouses and live with another participants spouse for two weeks as husband and wife.