A happy family is suddenly struck by misfortune, revealing the hidden truths beneath the surface. Tsuyoshi, who runs a small company, has been living a peaceful life with his mother and wife—until worsening finances push his business to the brink of collapse. Amid the crisis, Tsuyoshi begins reminiscing about the past. Twenty years earlier, when the family of three struggled in poverty, his mother decided to work at a pink salon to support them, while his older sister Miwa secretly posed as a nude model. One day, Tsuyoshi, training hard to become a professional boxer, visits a pink salon to unwind and receives intimate service from a new girl named Miki. Later, he discovers a business card labeled "Miki" in his drunken mother's bag, plunging him into shock and confusion. Forbidden relationships—between sister and brother, mother and son—emerge, challenging the very meaning of family bonds. A lust-filled domestic drama begins here.