“Elia’s Quest” – “The Showdown” [Campaign 3, Mission 5]

What should I do at the very beginning of the mission? When it's just Elia and Isabel? I don't know where to go. If I go to the town that needs to be captured within a week, a powerful demon appears soon after and kills me in two hits. And if I go to conquer castles, that same demon appears there too...