该作品讲述槌谷摇为普通的男大学生，饲养著一只白貂的故事。

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 human tenants. With his friends, Okojo struggles to adapt to life with humans, vacuum cleaners, and all the other things that come with human society.

北の山奥で生まれたオコジョさん。ある日、決死の覚悟でペットショップから脱走したオコジョさんは大学生の槌谷くんと出会い“しあわせ荘”に住むことになった。そんなオコジョさんは、かわいい容姿とは裏腹にとてもヤンキーな性格なのだった。槌谷くんたち人間は、一見ワガママに見えるオコジョさんに振り回されながらもドタバタ劇を繰り広げる。