After passing through the rocky Route 12 and the oasis in Route 13, you reach Tapu Village.
Explore Tapu Village
Go west from Route 13 to reach Tapu Village. Go west into the village and you meet Hau. You won't be able to go north from here because the Pokémon League is still under construction.
After the cutscene, go west to the Pokémon Center. There is a Veteran outside of the Pokémon Center whom you can battle if you have battled at least 160 Trainers and have used your pokémon's Abilities in battle. Veteran Angus has a level 36 Shelgon, a level 36 Gabite, and a level 36 Sliggoo. You get 3168 Pokédollars for winning. Afterward, he gives you Choice Specs.
A hiker in the Pokémon Center named Sill will trade you his Phantump for your Phantump. Tumptump will evolve into a Trevenant after the trade.
Leave the Pokémon Center, then go west from Tapu Village to go to Route 15.
Go north to the Aether House and go inside. Hau joins you, then you have to battle Preschooler Hunter, who has a level 32 Elekid. You get 384 Pokédollars for winning.
After the cutscene, go outside. You will have to battle a Team Skull Grunt that has a level 33 Drowzee. You get 1056 Pokédollars for winning.
Afterward, you get 5 Luxury Balls.
Now go south to return to Tapu Village, then go south and approach Acerola, then go south to reach Route 14.
To the left of the entrance, there is a hidden Pearl.
In the west side of the water, to the right of the stone platform, you can battle, some wild Frillish are surrounding a swimmer. Talk to the Frillish and you can try to capture or KO it. After you do, the swimmer gives you a Destiny Knot.
When you walk up the nearby steps, you will battle Veteran Brone. He has a level 36 Whiscash and a level 36 Honchkrow. You get 3168 Pokédollars for winning.
To the left, on this platform, you find TM30 Shadow Ball.
Go back onto the beach. Southeast of the route entrance, you can battle Fisherman Hisato. He has a level 34 Feebas and a level 34 Gyarados. You get 1088 Pokédollars for winning.
You can go up onto the broken road, then go east to get a Max Potion.
Go east to jump down the one-way ledge. To the right, you can battle Collector Kawika. He has a level 34 Larvitar. You get 1088 Pokédollars for winning.
Go south and down the ramp. There is a hidden Big Pearl to the left of the bottom of the ramp.
Go east and approach Acerola, who is standing in front of the stairs near the east side of the beach. She will tell you that her trial is up the steps.
Before you go up, you can go east and talk to the Preschooler. Both answers are correct. Offer to take Sandygast to a different beach and you will go to Ula'ula Beach with it. The Preschooler will give you a Stardust. Then you automatically go back to Route 14.
Go farther east to get a Max Revive.
Then go up the stairs where Acerola went, and Acerola will tell you that you have to go into the building and take a picture of the Totem Pokémon with the Poké Finder. However, the Totem Pokémon likes to hide, so you should investigate any weird happenings inside.
Acerola adds a special mode to your Poké Finder that you can only use in this trial.
If you are ready, go into the building.
Abandoned Thrifty Megamart
Go into the building and follow the path until you see a conveyor belt start moving by itself. Check on it and use the Poké Finder. Aim it upward to find a Gastly. Take a close-up picture and you will battle the level 30 Gastly.
Afterward, a Pikachu will go running past down below, so follow it. You will find a shopping cart moving on its own. Go up to it and check on it, then use the Poké Finder. Aim it upward and take a close-up picture of the Haunter. You will have to battle the level 30 Haunter.
Then you will see a Pikachu going upward, so go to the right, then go upward, and follow the path until you see some floating dolls. Go up and check on them, then use the Poké Finder. Aim the Poké Finder around until you find the Gengar. Take a close-up picture, and you will have to battle the level 30 Gengar.
After that, you will see a Pikachu to the left, going upward to some doors. Go to those doors. Acerola asks you to leave. Keep refusing to leave, then take a photo when you have the option to do so. The doors will unlock on their own. Open the door and the Poké Finder will automatically start. The pokémon is behind you! Turn the Poké Finder around and take a picture of the pokémon. You will have to battle it.
The Totem Mimikyu is level 35. It is weak to Ghost and Steel attacks. It can call ally pokémon into battle, such as Haunter, Banette, Jellicent, etc. The first time you hit Totem Mimikyu, it will do no damage, but it will break the Mimikyu's diguise so that you can damage it from then on.
Afterward, Acerola gives you Ghostium Z, and you can now catch pokémon inside the trial site. She also gives you 10 Dusk Balls.