+Anima are rare and mysterious human-like beings capable of transforming their body into the form of an animal, but they are ostracised from society by humans. Cooro, a young orphaned +Anima with the abilities of a crow, struggles to find acceptance and belonging. Having been found on a church altar as a baby, he knows little of his origins and his species despite the poor reputation they receive. Thus, he resolves to search for more of his kind.

Together with his newfound companions—Husky, Nana Alba, and Senri—Cooro embarks on a quest to meet other outcasts and discover their place in an unforgiving world. As the bond between the four +Anima grows to become unbreakable throughout their travels, a sense of adventure seems everlasting. However, the group soon realizes that finding somewhere to belong might prove more challenging than previously anticipated.

+Anima follows the hardships and adventures of Cooro and his friends as they learn of the difficulties and prejudice experienced by their kin.