Ran is a bright and energetic first year junior high school student who possesses supernatual abilities. Together with Midori (A troubled girl who posesses similar abilities) and her childhood friend Rui, the threesome are constantly embroiled in mysterious circumstances. Ran and Midori must learn to deal with their abilities and the prejudice and fear of those people who refuse to accept them because of it.

The story is set in "No. 6," a future model city in 2013. Raised as a top-ranking elite since the age of 2, a boy named Shion lives in an exclusive area in No. 6. On the night of his 12th birthday, he rescues a boy who calls himself "Nezumi" ("Rat"). Nezumi ran away from the city's Special Security Area. From that moment on, Shion's life is changed forever...