In the game, the player takes the role of Ibuki, a college student living on his own in an apartment complex. A lover of cats who often feeds strays in the park and takes injured cats to the vet, Ibuki is visited in the night by the Cat God, who offers him one wish in return for his kindness to animals. Ibuki wastes no time in his reply: “I want a catgirl!”. The cat god immediately announces his wish is granted and then vanishes, leaving Ibuki to wonder if it was all a dream.
Several days later, Ibuki is on his way home from work when he discovers a carboard box left near his apartment. Hearing the sound of a what he believes to be a cat, Ibuki opens the box to discover not a cat but in fact a catgirl, naked and sleeping. Ibuki takes the catgirl to his flat, where she reveals her name to be Mikan, and explains that she was sent by the catlord to serve him. Over the next few days, Ibuki discovers that the situation may not be as perfect as it first appeared, as a number of unwelcome visitors accidentally moved from the cat kingdom to our world alongside Mikan.