You'll see Ann carried by the monster and then the camera view will change, and now you're controlling Kong. Move ahead, to the stone way's end.
Be careful: do NOT stand in one place for too long, or Ann will die.
From there jump towards the tree's branch...
...and then on planted wall. Move right and jump on the tree at the road's end. Now jump on the shelf (orange arrows).
Again, climb the wall from the end of the shelf and approach it's end.
Take advantage of branch, jump on another one, and get to the wall. Walk down at way's end and you'll stand on the ground.
Walk ahead and climb the vertical wall up (if you don't hurry, some flying monster will attack you).
Walking at the top, approach the edge again.
Jump towards the branch, on another one and finally land on the ground.
Moving forward, you'll reach the vertical wall. Climb up (get rid of some flying creatures, who will attack you there, and don't ignore them trying to move further).
Move small bit on the higher shelf (two monster will try to kill you, but you can leave them alive) and climb on the wall. You should reach the higher level.
Walk on the next wall and jump to another one (located on the other side).
Now, jump twice and get at plants located on the precipice. After a while, you'll find yourself on the ground again.
Reach the planted the planted wall aiming up (spirally). Climb it.
Short cutscene will turn on. Kong will be attacked and Ann will escape from the gorilla.
Now, you're standing in the arena, where you'll have to fight with (I called it) 'mother'. The monster will be flying around the round field and when the camera view changes, he'll attack. After few hits (attack with paw, don't try to catch enemy), some smaller opponents will try to kill you, but you shouldn't have troubles in defeating them. You can also turn Kong's rage on, by hitting his chest with paws. If that happens, the environment will change it's colours.
After a few hits, the 'mother' will fall down. Approach her and finish the monster off for good.
The victory won't end the mission. Now, you've to capture Ann again.
Approach and destroy the gate, but remember to throw away column lying on it first. Move ahead and under rocks.
Slide the wall down, and bounce from it in proper moment to reach the tree's branch. From there, move on the ground again.
When the camera view changes, two dinosaurs will join the action and try to eat Ann. You've run up to them as fast as possible and get rid of opponents to save 'beloved one' (sometimes, enemies will hide behind environment's elements). The woman will pass through the narrow, wooden bridge. You should take the planted wall to fallow her.
You will reach the place, where Ann will go through the opening in the wall (too small for you). To catch 'beloved one', you must quickly run on the wall and approach her. When that happens, the romantic scene will take place :).