"Hajime-kun? It's Horiuchi Hajime-kun, right?" I heard a strangely familiar voice from the neighbor's house where I went to say hello. - That person was Ayaka-sensei, my tutor when I was a student. - While I was happy to be reunited with the person I had been in love with for the first time in a while, I felt a little pain in my heart when I learned that Ayaka-sensei was getting married. - Then, on the night when the moving work was finished, as I was thinking about Ayaka-sensei in agony, I heard the couple's activities and Ayaka-sensei's singing from the other side of the thin wall...