A pet raccoon dog with escape artist instincts crashes into an ordinary student's life and refuses to leave, spawning 51 episodes of escalating absurdity that treat mundane domesticity like it's the funniest premise ever written. The show doesn't need plot twists or emotional arcs; it just watches two mismatched creatures generate chaos in the same apartment and finds endless material in the gap between Haruka's resigned acceptance and Okojo-san's scheming. This is sitcom logic stretched across two seasons, where a talking animal and the human stuck with him become the only two people who make sense to each other.

Okojo-san is a white ermine kept at an exotic pet shop run by a greedy manager, until he plans his way out. After the commotion of his escape, he is left unconscious in a garbage can, where university student Haruka Tsuchiya discovers him. Haruka takes him for a ferret and brings him home to the Shiawase apartment complex. There Okojo-san meets other pets, among them a mouse named Chorori, along with a cast of odd human residents. Together with his new friends, he struggles to get used to people, vacuum cleaners and everything else that comes with human life. The gag comedy runs on absurdity and on Okojo-san's habit of turning everything into melodrama.