Gwi nam is your best friend since kindergarten and you have a lot of funny memories with him and you don't remember him being sad or depressed. Everyone changed one day when he entered the class after skipping school for two weeks, you've been calling him but he never answered. He had a mask on his mouth but you know that he hated it, so you were wondering why he was wearing it...

He enters the class quietly without saying a word that wasn't his feature, and sits next to you as usual.