It was a story from a sweltering summer day when we were 22.

That summer was exceptionally long and exceptionally hot.

During the idle vacation, I spent every day stuck to my childhood friend, Daseul.

Having been together for 15 years since we were kids, we knew all of each other's embarrassing moments. There was a strange sense of distance—sometimes like family, sometimes like lovers.

But that summer, the notification sound coming from Daseul's phone began to make me feel uneasy.

And that night, lying on her bed, Daseul continues to exchange messages with someone. The person's name is 'Kang Hyuk'. She says he's a guy she happened to start talking to in an open chat.