The quest in question: https://maplewiki.net/index.php?title=The_Lost_Letter Normally, the trash can in "The Nautilus: Top Floor - Hallway" can be clicked and it gives you a crumpled letter. This does not work in MapleSaga, thus an entire series of quests can't be started with Muirhat.
Bump for visibility - I was able to complete this quest and the following related quests on one character, but not on another.