When rock says that the enemy is moving along the river, at that point I am flying over a little stream. But I can see a big river to the right.
This got me confused. Which river is he talking about ?
But I tried both scenarios:
First I kept flying over the little river. At the end you can turn left or right. When I turn right, I quickly get landing instructions. Nothing else happens.
In my next try, when rock says that the enemy is moving along the river, I turn right and fly towards the big river. Again I get landing-instructions before I see any enemy. I keep on flying into the mountains, but nothing happens.
OK, my guess is that it is the big river I should focus on. The little one is more like a stream or a creek. I will try it once more later today, keeping my eye on the ABRIS.