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

Having idle conversations and living with someone. Natsuki reminds you of these warm feelings you had forgotten about after living alone for so long. Natsuki works really hard for you, and in return, you try to reward her with a beautiful view...

It's been quite a few days since Natsuki first arrived and the fun and lively days continue. However, you start feeling anxious. Despite how pathetic you may feel, Natsuki always cheers you on. You then come to a decision..