During the scorching summer, Shinohara Sumi finds herself compelled to attend supplementary lessons, until a sudden occurrence changes her life. A mysterious young man, Yoshino Mitsuru, dramatically jumps into her classroom through the second story window. Day after day, he assists her with her studies, and Sumi's affection for him deepens. However, as she starts to investigate the loneliness that hides within Mitsuru's eyes, she realizes there may be more to his story than meets the eye.