A white ermine Okojo-san lives at an exotic pet store run by a greedy manager, until he escapes one day. 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 mouse Chorori, and the various eccentric hum...