It's a map with some explanations about draconics. . . "The force of evil will destroy the world" blah-blah-blah. . . So we go there then

The sage must've made it fire-proof and then forgot about it.

These ashes. . . He was burning some parchments or paper. . . There's one intact!

If there was at least one chest with treasures. . .

Pretty cosy! Our host must've spent a lot of his time in this laboratory.

It's not all bad though - the explosion opened the way to the dungeon bellow. . .

Well, that was a bit of a mistake. . .