Swamped

There's a mirror on the back. It's completely undamaged, though - looks like the knife didn't go all the way through the tile.

Your immediate questions are, why was a mirror hidden on a piece of ceiling, and why was a wizard looking for a mirror hidden on a piece of ceiling.

Well. Maybe it has something to do with the map. On nothing more than a whim, you hold up the map so it's reflected in the mirror, and... it looks like the same map, only backwards.

Except, that's not entirely right. The map in the mirror looks a lot cleaner, not like a worn-out page. So... is the mirror showing its appearance from years ago? Or maybe there's just something weird about the lighting.

Well, now you're looking at the reflection a little more closely. And that's when you spot something odd.