Yep, the room with (what always appeared to me to be) hay, you just examine the tile where Mog was standing.

Raiden has the Quick spell, you'll need to have Odin and take him to the statue of the queen in the ancient castle (go five steps down from the right throne in the center chamber and press confirm, then go down a secret passage in the room with a bookcase). You'll lose Odin forever, but you can learn the spells he teaches at better rates by getting the Crusader Esper, after defeating all eight dragons.