The story revolves around a protagonist known as "Starry Sky" in Japanese symbols but goes by the name "Nasa." While taking his high school entrance exam, Nasa meets a stunning girl named Tsukasa. He believes that fate has brought them together for a romantic relationship, but an accident occurs, preventing him from taking the exam. Tsukasa helps Nasa with his injuries, and he confesses his love for her. She agrees to date him only if he marries her first. Despite acing his entrance exams a year later, Nasa opts to work part-time and live independently instead of going to school. When Nasa turns 18, Tsukasa returns, and their mysterious, romantic, and happy married life begins.