Chapter 8: Mount Hokulani
Use Charizard to fly to Heahea City. Heal up at the Pokemon Center and then head right until you get to Hano Grand Resort. Hed north and enter the building. A man named Faba will greet you here. Agree to go with him to Aether Paradise. A lengthy cutscene follows. Head to the left, north, and then to the right. You'll be introduced to the Aether Foundation's president, Lusamine. A strange creature will appear titled ???. Walk forward to battle it. It's weak to Ground types moves but will flee before you defeat it. Lusamine will identify it as an Ultra Beast. Wicke will then give you TM29 - Psychic and send you off to your next island.
As soon as you get to the island, Hau will challenge you to a battle. He's got a very strong Lv. 28 Raichu that knows Psychic, alongside a Lv. 28 Flareon and a Lv. 29 starter. Heal up at the Pokemon Center and enter Malie Garden to the left. Head to the right perimeter and defeat the trainer here. Grab a Grassy Seed from an Item Ball further up and then head back to the left side of the garden. On the left side you can pick up a Luxury Ball and defeat the small trainer walking in a circle. Continue north and cross over to the island. You'll find a Rage Candy Bar underneath an umbrella. Continue north and to the left to face another trainer and find a Zygarde Cell. Head straight north for a Big Mushroom. Then go see the professor sitting on a bench in the center of the island.
After some dialogue with the professor, exit the garden to the south. Lillie will be waiting for you here, she'll ask for your help again. Make sure to grab the Zygarde Cell that is sparkling from beneath the truck here. Head left a bit more and you'll quickly run into a very familar face... Professor Oak. Head north towards the library and you'll run into Lillie again. Head to the second floor of the library whenthe first cutsecne ends. Exit the building after another cutscene and head south and to the left out of the city.
If you speak to the lady upon entering Route 10, you can agree to an optional sidequest to find her 8 Stuffuls on the route. You can find a Paralze Heal in an Item Ball next to the first trainer. There is a Stufful behind this first tree. There is also a pile of berries next to a lady who will heal your Pokemon and the second Stufful is hiding behind the palm tree. The third Stufful is hiding north of the second trainer on the route. The next Snufful is behind the sign just north of this and is also next to a Zygarde Cell. Head left into tall grass to find the fifth Stufful and an X Accuracy.
You'll find another Stufful in the open on the left side of the route and there is another hidden in the tall grass to the right of it by another trainer. Head back down the trail the way you came and you'll find the final Stufful in front of a bush accross from the man in blue. Talk to the old woman again and she'll give you a Nevermelt-ice and 15,000 pokédollars for your troubles. Now, head back up the route until you get to the bus stop. Confront the Team Skull Grunts guarding the bus stop at the north end of the route to battle them. After you've beaten them both, Professor Kukui will come and talk to you. Answer yes at the bus stop and get on the bus!
Heal up at the Pokemon Center if you need and then head towards the building. You'll need to beat a trainer named Molayne to pass. He has a Lv. 29 Skarmory that can be tricky, but an Electric type should be able to take it out. Enter the building after you've beat him. Go straight through two doors and you'll enter a room with Sophocles. Say "yes" when asked if you like the Festival Plaza (he runs it, don't hurt his feelings now). His trial will start after the lights go out.
Trial of Sophocles
He'll ask you a series of questions about familiar Pokemon sounds. A Pokemonn will attack after each answer. If you'd like the answers in order, here they are: Pokémon Center (Grubbin), Rotem Dex (Charjabug), Charjabug (Charjabug), A Totem Pokemon (Totem Vikavolt). After you answer the fourth question, a Lv. 29 Vikavolt will appear. It will call Lv. 27 Charjabug as an ally Pokemon. A strong Rock or Fire type Pokemon will make your life easiest. Once you defeat the Vikavolt, you'll get Electrium Z. You'll also get the Steelium Z from Molayne along with the Professor's Mask. This marks the end of the Mount Hokulani trial.