Mao, a wife who is living a happy life with her husband, Toshio, who is a practicing doctor. One night, Toshio's younger brother Shingo suddenly arrives at the Hamasaki family. In contrast to Toshio, who casually says, "He's a free man, so just leave him alone," Mao is terrified by Shingo's words and actions and can't control her anxiety. This is because Shingo knows the secret of Mao's past. Such uneasiness of Mao turns into reality. "You don't want your brother to know about Mao's past, do you?"
