Walkthroughs for Campaigns and Maps in WoGA.

Could you please provide guidance on how to complete the second mission, "Evil Way Home," where I need to build the Grail Temple? The Seer needs to bring an Archangel, and in return, he will give the "Flight" spell. However, I only have an Angel; where can I upgrade it? A Zombie suggested that the Fortress is in the Dungeon, but I couldn't find it there. I'm not sure what to do next. Perhaps someone who has completed the mission can offer some advice.