Who was he?

Noah is a shy boy who along with his family is new to Asphodel society. There was a music academy near the society and he joins it. He has to walk to the academy alone and he is scared to do so. Near the gate of the society he sees a boy who happens to go to the same academy. The boy's name is Mnemon. They become good friends. After a few months Noah makes another friend but when he waits for Mnemon to walk to the academy together, he never comes. That day after the academy Noah goes to the apartment Mnemon had told him he lived in. But the door is locked.....................

Read to find out what happened to Mnemon!