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 obtain the Sword of the Gods, which is guarded by a wild army, but I only have 4 heroes and Crusaders and Monks from field Havens. 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 Life Magic skill, and I'm using the "Song of Peace" and "Guardian Angel" spells, but they still get destroyed! Can anyone suggest how to complete this? Specifically, on Champion difficulty.