Explore the cave behind the waterfall | Walkthrough The Last Guardian Guide
Last update: 15 December 2016
Enter the cave and start by finding a barrel for Trico. Then, climb onto the beast and point him to the large hole in one of the walls. After Trico reaches there, jump into the large water reservoir in the next chamber.
Here, you have to dive for the first time (the X button) within a small distance of the locked grate. This will allow you to find a small hole shown in the above screenshot, which you can swim into. Follow the tunnel and after you get into a new location, climb the ladder. This way, you will get to a spot with a lever.
Return to the main chamber. Command Trico to jump into the water and jump onto his back. Now, aim at the water surface and point Trico there. The beast should diver and swim up to a much larger hole right above the bottom. Allow Trico to swim with the boy into a completely new chamber.
In the new part of the cave, make sure that you are still on Trico's back and command him to jump into the water. Swim with Trico into the location shown in the above screenshot. Here, you can jump over to the ledge and explore the small room. In there, you will find a barrel for Trico.
Jump into the water again and swim up to the shut gate. Just like you did earlier, you have to dive and find a small tunnel under the gate.
You will get under a new lever, but without Trico's help, you will be unable to reach it, because it is too high up. Turn towards the grate and call on Trico (as shown in screenshot 1). You have to wait for him to jump into the water (shown in screenshot 2), which will form a large wave. Use this to your advantage and grab onto the ledge up above. You can now pull the lever.
Climb onto Trico and just like you did earlier, command him to dive. You will reach a new flooded tunnel. During the ride, the boy will suddenly start to drown and you will progress into the next scene.