Hotaru Shirakawa was in love with Inami Ken and openly confessed her affection for him. The two of them embarked on a happy romantic journey until summer brought them face to face with Shirakawa's close friend, Tomoe Tobise, who had an irresistible charm. This left Ken in a predicament - to keep his promises to both Shirakawa and Tobise or take a chance that could result in losing them both.