Yui makes you dinner as thanks for helping her out with her studies. You both spend somee fun times together, but then Yui gets the results of her mock exam and is depressed. One snowy night before her entrance exams, you spend a nice evening together

Your little sister, Natsuki, suddenly shows up in the middle of your busy days. Apparently she came to take care of you while she was on her summer vacation. This is the story about you and Natsuki one summer