Marion builds a fortress called rationalism to keep the world out. When an older woman dismantles it piece by piece, he discovers that what he called philosophy was just fear wearing a smart name. The movie doesn't let him off easy for learning this, it makes him pay for every moment of awakening, and that's where the real story begins.

Marion builds his identity around reason and logic, scoffing at sentiment as weakness. He calls his philosophy rationalism and brushes aside anything that resembles affection. With most students gone from his boarding school for the summer, he and a few friends stay on campus, proud of never letting feelings rule them. Then he meets Sarah Vieda, a much older courtesan, and the two begin a physical affair. Their relationship blossoms in ways Marion never anticipated, and his rationalism turns out to be a shield for emotional immaturity. As he learns to love under her care, he has yet to grasp what the affair will cost him and his friends. The film is a drama and romance adapted from Takemiya Keiko's 1976 shoujo manga.