Continue up the stairs on the right, and you'll soon see a save point.
After reaching the save point, the "Clean House" quest will refresh. You can teleport back to turn it in, but there's no rush if you'd rather not. Teleport back to the驿站 (Post Station), find the old man on the roof from before, and talk to him. He will give you a Shadow Armament called the "Feather Bow".
Once you have this bow, you can explore areas on the map that require bow shots, though most of them just contain materials.
