Yuka Hirose and Yuusuke, who were once in a relationship, have each married and then unexpectedly reunite. With their respective marriages having grown cold, they choose the path of infidelity and begin a series of secret trysts. Each time, consumed by pleasure yet determined in their actions, they answer their spouses' phone calls mid-sex. The thrill of betrayal draws them closer together, deepening their bond. A heartbreaking and shocking tale unfolds as their desperate efforts to protect their secret collide with an overwhelming, reason-shattering passion.