Perl: I also started this mission about 6 times before I read a walkthrough online. It turns out that you absolutely must not capture the lower castle, but it's better to capture the upper left one first. And then quickly develop and capture the upper right one (it's easier when Gilraen isn't home :)). Then the rest is easy.

But I'm having trouble with this mission. It's so frustrating. :( I killed everyone, captured the castles, killed the druids in the center, but the quest still requires me to kill a hero. What should I do? Is this a bug? I have a licensed copy.