Beings who possess animal-like powers walk among humans in this alternate universe. These mysterious mutants, the +anima, are shunned by society. Four outcasts in particular–Cooro, a boy with crow-like powers; Husky, a fish-boy; Senri, a bear +anima; and a girl named Nana, who wields the power of the bat–search for others like themselves while trying to gain acceptance in a world cruel to anyone or anything that is different.