The main character is senior high‑school student Nora Handa. His mother adopted a girl named Sati Yūri, who lost her mother and for some reason does not live with the father. In addition, Nora has a childhood friend Miti Kuroki, who heads the school committee of public morality and is friends with Yuki Asuhara, who behaves like a "kogyra" but remains loyal and reliable. One day on the way to school, Nora meets a girl named Patricia in the park. She claims she is the princess of an underground kingdom and has come to the surface to destroy life. However, as soon as she touches the first resident of the "upper world," she loses her feelings, and Nora has to help her. Patricia asks the hero to reveal the "secret of life," and Nora begins explaining it—using an erotic magazine they found there in the park.
