Due to being disowned by her grandfather, Aoi meets him for the first time, and upon seeing his grandson's face, he can't contain his joy. Witnessing his smile, Aoi offers to care for him, but as she spends time with the elderly man for the first time, she becomes drawn into his abnormal sexual desires. Complying with her grandfather's lewd requests, he displays an unnatural affection toward his granddaughter. They engage in deep, tongue-twisting kisses, devoted blowjob sessions, and even have unprotected sex like lovers. This strange relationship blossoming between grandfather and granddaughter leaves her utterly confused.