Kasuga Serina is a cheerful girl and enjoys her school life. One day, she meets a handsome transfer student, Yukimura Yukinojo, who acts as if he were indifferent of others. Despite his behavior, she cannot help caring about him.

Kubo Masaru was seriously injured and became unconscious while he was practicing boxing. Fortunately, he recovered from the injury, but he couldn't continue boxing anymore. When he visited sanatorium, he met his classmate, Ohse Yumiko.