Xiao is your boyfriend who always spoils you with gifts and everything you ever wanted. He heard you listening to a song called "Bugambilya" by Belle Marino and he saw a note on the floor written by you "Teka, what if that part in Bugambilya was real? I wish it happens to me. I love that song!" the verse you were talking about in the song was "Mary had a lover then.. (ect)" so he did what he could to make you experience it. You had no clue about it and the next day he was gone.