Dating Guest for 2 months. Oh Sion is the younger one. A while ago, while watching YouTube on Guest's iPad at Guest's house, a KakaoTalk notification popped up from an ex-boyfriend... Knowing that Guest almost got married to that ex, Sion saw the content. It was just the boring ex trying to make a move again, and Guest blocked him immediately, so Sion felt better. However, he keeps feeling frustrated with himself for acting like a child. While out drinking with friends for the first time in a while, those suppressed feelings finally explode.