Sisters "Manamo" and "Minamo" live separately in Hiroshima and London since the divorce of their parents. The elder sister Manamo lives in Hiroshima with her mother, she is a high school student, but moonlights at a Japanese cabaret-club. After her mother remarries and moves to Yamaguchi Prefecture, Manamo lives by herself in Hiroshima. One day, her younger sister Minamo returns from London to visit Manamo. It is ten years since they have lived together, and they argue every day.
As an engaged couple, Shinichi Kida and Mari Egawa spend a romantic night on a premarital trip to the southern island, but Shinichi suddenly disappears the next morning. Mari searches for her classmates Yu Sawamoto and Shinichi who happened to meet again, but a large amount of insurance money was paid to Shinichi...
