After discovering her husband's infidelity, Saeko (Mao Ichijo) found a deep rift forming in their relationship. Yet, to avoid worrying her son Kazuhiro, she continued to act cheerful and upbeat as always. Behind her smile, however, she carried a dark secret she couldn't share with anyone—even her son. The private detective she hired to investigate her husband's affair demanded her body as payment, and she had no choice but to comply. Tormented both emotionally and physically, she endured each day in silence. Then one day, her son Kazuhiro witnessed the encounter. That shocking moment would change her life forever.