Thirteen years after their last meeting, Riona returned to live with her father, reminiscing about her late mother while adjusting to life in the home of her biological father, now an unsuccessful erotic manga artist. Embarrassed, she refers to him as "uncle," creating an odd dynamic between them. Though her face still retains a youthful innocence, her mature, feminine body awakens sexual feelings in her father. These emotions gradually intensify until he can no longer suppress them, and the forbidden door swings open. A complex, shocking relationship unfolds, transcending the boundaries of family.