My sister Natsuki comes to you who is swayed by busy days. Natsuki, who came to teach her brother's life during the summer vacation, takes good care of you so that you can lead a proper life alone. This is a summer story about Natsuki and you.

Casual Conversation, day spent with someone. You will remember the warmth that you have forgotten for a ling time by being with Natsuki. Natsuki works hard for you. You prepare a special view to respond to that feeling.

It's been a few days since Natsuki came, and the fun and noisy days continue. But at the same time you begin to feel a slight impatience. You make a decision for Natsuki, who still cares for you even if you show her tiredness and pity.

Natsuki spills his true feelings on your cold words. Your younger sister, who cannot be honest, and you, who are stubborn, will know each other's thoughts for the first time. Eventually, the small but important days have come to the end of summer vacation.

You live and work at a bathhouse that’s in danger of going under and get worked to the bone by the owner's granddaughter, Minori. You’re both very close friends, almost like brother and sister, and another fun-filled day is about to begin.

You and Minori go to a local summer festival. Somehow, Minori frolicking in her yukata makes her seem a little different than usual. That night, you both enjoy the fireworks and then have a serious conversation.

Minori decides what she wants to do in the future, but she realizes how difficult that will end up being. She doesn’t want to change, but she realizes she has to. The solution that Minori comes up with ends up shocking you...

You somehow agree to go along with Minori’s experiment of how it would feel if you two were married. She then tells you why she wants to protect the bathhouse, which ends up making the bond between you two stronger.

You end up running into a college student named Amatsuki Mashiro, who lives in the same apartment building as you. Your first encounter doesn’t go very well and she ends up calling you “Mr. Pervert,” but this leads into a more meaningful relationship.

Mashiro spent most of her life concentrating on gymnastics and is now troubled because she feels like she can’t do anything else. You then help her with practicing for interviews, cook with her, and other things, making you closer. You also feel troubled about work and you two start talking a lot more.

Mashiro still struggles to find a job, but then you end up finding the perfect job for her.

Mashiro thanks you for helping her move forward, which brings you happiness as well. The girl who loves gymnastics and her “Onii-san”... Where will your story go next?

You and your junior Kotokawa Akira spend your days together at your school’s Gardening Club. Akira is always smiling as you both tease each other, but as soon as summer vacation starts, she seems a bit sad. Your unforgettable summer with Akira in the Gardening Club is about to begin.

The Gardening Club prepares for an incoming typhoon. Despite not having school that day, you and Akira both decide to come to school, and end up having to spend time in the club room until the typhoon passes. As the storm gets stronger, you and Akira get closer.

After the typhoon passed, you and Akira were about to get closer, but you pull back. Then Akira tells you something she’s been holding back this whole time. And because of that, even though you were looking forward to the next day, it suddenly turns awkward.

The end of summer vacation. In the fading club room where you personal belonging are gone, you touch the gardening notebook that Akira has forgotten and the feelings spelled out in it. Remembering everything, you take a step that you couldn't take that day to a lonely junior who is about to leave alone.

You head home to the country for the first time in a while and your younger sister Natsuki greets you with open arms. She praises you for how hard you've been working and living alone in Tokyo, but she tells you that she's also wondering if she should go to Tokyo for high school. On a cool, summer night, Natsuki tells you her dreams.

The two of you had decided to keep the public bath going, but Minori seems troubled at how difficult this venture ends up being. One wintery day, Minori seems to be acting a bit different and wants to tell you something.

Saya very suddenly becomes your tutor and you end up feeling very comfortable around her because she's so nice and positive. Saya also seems very happy that she's able to help someone out.

Saya continues to be your tutor and look over your mock exams. She seems very confident that you're going to be able to pass your college entrance exams.

You've finished your exam so you and Saya go out to celebrate. You both seem excited that this might actually be a date and then Saya tells you a secret while you're riding the Ferris wheel.

You have failed your exam and you don't have the heart to face Saya. Surprisingly, Saya also had a secret. Because you're both so awkward, you feel comfortable when you're together. You and Saya decide to ride the Ferris wheel one more time, so you can officially give your relationship a name.