Walkthrough of the Life campaign on Champion difficulty.

I can't seem to beat the second mission! There's no town, only 4 heroes from the previous map - Lysander, Proefo, and two others. To complete it, I need to get the Sword of the Gods, which is guarded by a wild army, but all I have are 4 heroes and Crusaders and Monks from field outposts. I can't imagine how to do this! The army consists of Medusas, Minotaurs, Nightmares, and Ifrits. I've tried everything! I've leveled up Lysander's Warfare skill, Proefo's Healing skill, and I'm using the "Song of Peace" and "Guardian Angel" spells, but they still get destroyed! Can you give me some advice on how to beat this? Specifically on Champion difficulty.