Minami stars as a devoted wife living a quiet life with her husband, Hideto. While working part-time at a convenience store, she has a chance encounter with Hideto's cousin, Yasuharu. The couple invites him into their home, unaware of his dark intentions. While Hideto is happy to be reunited with family, Yasuharu immediately begins making aggressive moves on Minami behind her husband's back. Despite her constant rejections, she is unable to escape Yasuharu's escalating lust and is eventually forced into a secret, forbidden affair. The film explores the psychological toll of her betrayal as the boundaries of family and fidelity are violently demolished under her own roof.