Minami, visiting her uncle's house for the first time in a while, finds him living alone, never having married and continuing his solitary bachelor lifestyle. Unbeknownst to him, Minami has long harbored secret feelings. Struck by her stunning beauty and matured figure, her uncle struggles to resist the growing temptation, but his self-control eventually reaches its limit. As they cross the forbidden boundary into an illicit relationship, a new, intense emotion arises between them, leading to an unprecedented depth of pleasure.