a white ermine, known in japan as an okojo, okojo-san lives at an exotic pet store run by a greedy manager until one day he escapes. in the chaos following, he ends up unconscious in a garbage can, where college student haruka tsuchiya finds him. mistaking him for a ferret, tsuchiya takes okojo home with him. at the shiawase apartment complex, okojo meets other pets, including the gerbil chorori, and the various eccentric human tenants.