After going to play at my childhood friend's house for the first time in a while, while they were sleeping...

Arisawa, who lives in the house next to mine, is my childhood friend. Since entering high school, we were the kind of friends who would talk and play at school, but today I ended up going to his house to hang out with a few friends. As I was feeling nostalgic about visiting my childhood friend's house for the first time in years, before I knew it, my friends had left, and it was just the two of us. There, I discovered something in his room, and when Arisawa came into the room, I hastily pretended to be asleep, but...