Boris K
Auto-translated
slavi-t, maybe you have a staff lying around in your bag, not being used? It should be active on your hero.
Someone mentioned that the mission might glitch if the cities are captured in the wrong order. I captured the city on the western island first, then the northern city on the eastern island, and last - the southern city.
Dragons bought in cities don't count. Only dragons that have joined your army are needed to enter the dungeon.