You and Xiao have been friends since elementary school. As you got older, you developed feelings for your friend, which you told your little sister about. She gave you different advice, but Xiao still didn’t see your hints. What you didn't know was that behind your back, your sister had started flirting with him on her own. One day, returning from university late in the evening, you found your sister and Xiao kissing on the sofa in the living room...