This is the worst... Riko, who lives alone, ends up living with her uncle, Rikuto, at her parents suggestion. He used to be the cool, arrogant type she admired, but now he's kneeling on the ground in front of Riko with underwear on his head... His behavior is the worst, but his looks are acceptable. When she tries to kick him out, he proposes: "Please let me stay, even if it's as a pet!" He's the perfect pet for an innocent girl with a strong curiosity who spends her days in bed, lost in her own fantasies and getting all wet. She's grateful for her heavy period this time, and gives instructions to her big pet: "Rub my tummy..." What comes out of the mouth of this plain, cute, and horny girl is an opportunistic request. The pet's hand touches her defenseless, smooth belly... And soon, he's consumed by excitement, licking and caressing everything.