After passing through the Ancient Poni Path and walking along Poni Breaker Coast, you reach the Ruins of Hope.
Ruins of Hope
In the Ruins of Hope, follow the path eastward. Approach the door, then after the cutscene, go through the door.
Go north to see a cutscene.
You have to use Machamp to push the stones to open the path to the north. If you make a mistake, go south to leave the area, then go north to go back in. The stones will be back in their original positions. If you just want the answer, click the button.
After you solve the puzzle, go north to the next room, then go north to start a cutscene. After that, and return to Seafolk Village. Another cutscene will begin when you arrive.
Afterward, go west from the tree and there will be another cutscene.
Exeggutor Island
When you arrive on the island, there will be a cutscene. Afterward, go west and talk to the nearest Exeggutor to battle a level 42 Pinsir. You can catch or KO it.
Do the same with the other two Exeggutor.
Then go north and check in the small cave up ahead to find a hidden Big Pearl.
Go east and talk to the Exeggutor. It will lift you up to a higher level of the island.
Go east from there and use Tauros to break the boulders. There is a hidden PP Up north of where the boulders were.
Go southeast from there and break the boulder that is partly hidden behind a palm tree. There is a Totem Sticker where the boulder was.
Then make your way west and north. Go up the ramp and check on the pedestal. Say Yes to take the flute. After the cutscene, your next destination is Vast Poni Canyon.