Returning to my hometown after a long time, my little sister Ai, whom I've always been close with, welcomes me energetically. That night, Ai crawls into my futon and asks, "Big brother... can I... sleep with you?" As I'm confused, she confesses, "...I love you, big brother. I know it's wrong. But... I can't suppress these feelings." I was bewildered by how she had grown from a child into a young girl, but since we felt the same way, I couldn't hold back and connected with my sister...