Walkthrough tips, Discussion of Campaigns [Heroes 5]

OK!!!:mad: This mission (No. 3) is really getting on my nerves!:mad:
As Ann suggested, I gathered 27 dragons on nearby islands! But the portal doesn't care! I completed all the quests, but it still doesn't care! I checked the mission list, and there are checkmarks everywhere, but not on the dragons!
And finally, where is this capital? Because to build a dragon crypt, I need a castle, but it tells me that I can only build a castle in the capital!:(
Help me..........