Warlock – “Raelag’s Offer” [Campaign 4, Mission 5]

Yes, I've been exploring this dungeon for three days now, and I've already searched everywhere... but it's no use.

Added 6 minutes later

I went there, but there's no one there(((I guess I'll have to restart the game.

Everything is correct - the entrance to the dungeon is behind the blue guardian, then in the dungeon, find the first two-way portal, then go down and then to the left (if you look at the mini-map) - you will come out to the top, and from there it's a stone's throw to the desired garrison. And also, both heroes need to reach there.