In the north end of Po Town, you find Shady House, defended by many Team Skull Grunts.

Explore Shady House

Go all the way to the left and go through the door in the left wall. There is an Ice Stone above the empty swimming pool.

Go through the door to the left of the stairs. In this room, you can battle the Grunt to the right of the fireplace. She has a level 35 Haunter. You get 1120 Pokédollars for winning.

Keep going to the right, through a couple of doors, to find a kitchen with a note on the floor. Read the note to find out this month's Team Skull password: Tapu Cocoa. It also says that a true Team Skull member always answers questions with "No!"

Go south in the kitchen to find a Heal Powder.

Go back to the first room of the mansion. To the left, you can battle a Team Skull Grunt who has a level 35 Mareanie. You get 1120 Pokédollars for winning.

Go through the bottom-left door to find a Max Revive. Then go back out and go through the upper-left door to find another note with this month's Team Skull password: Beat Up.

Back in the first room of the mansion, go to the right of the stairs and you can battle a Team Skull Grunt who has a level 34 Zubat, a level 34 Gastly, and a level 35 Salandit. You get 1120 Pokédollars for winning.

Go up the stairs.

Go to the left, then go up and go through the upper-left door. You find TM36 Sludge Bomb.

Go out, then if you go through the next door on the left, you have to battle a Team Skull Grunt who has a level 35 Rattata. You get 1120 Pokédollars for winning. After that, you have to battle a Team Skull Grunt who has a level 35 Raticate. You get 1120 Pokédollars for winning.

Go back to the hallway, and go through the bottom-left door. You have to battle a Team Skull Grunt who has a level 35 Fomantis. You get 1120 Pokédollars for winning.

Go to the left of that Grunt to get an Iron. Then check to the right of the Grunt to find another note with this month's Team Skull password: Golisopod.

Leave this room, then go to the right and you can battle a Team Skull Grunt who has a level 34 Wimpod and a level 35 Drowzee. You get 1120 Pokédollars for winning.

Go to the right and talk to the Grunt who is standing guard at the door. Give him the three passwords (Beat Up, Golisopod, Tapu Cocoa) and when he asks if you are sure, say "No!" He will move aside.

Go through the door that the Grunt was blocking.

Go to the right and get the Escape Rope to the right of the open window.

Below that, you can battle a Team Skull Grunt who has a level 35 Golbat. You get 1120 Pokédollars for winning.

Now go through the open window, then go north and go through the door that the two Grunts are guarding.

Step forward to start a cutscene. You will battle Team Skull Boss Guzma. He has a level 37 Golisopod and a level 36 Ariados. You get 4320 Pokédollars for winning.

Guzma will leave. Before you leave, check the treasure chest to get a Buginium Z. You can sit in Guzma's throne if you want.

Now go back the way you came to leave the mansion. Go south from the mansion and there will be a cutscene. After that, you should go fly to Tapu Village and go north to Aether House.

Inside, after you learn some bad news, Gladion storms in and battles you. Team Skull Gladion has a level 37 Golbat, a level 38 Type: Null, and a level 37 Sneasel. You get 3040 Pokédollars for winning.

Afterward, Gladion insists that you go with him, so say Yes if you are ready.

After a cutscene, the Ula'ula Island Kahuna challenges you. Island Kahuna Nanu has a level 38 Sableye, a level 38 Krokorok, and a level 39 Alolan Persian. You get 6240 Pokédollars for winning.

Afterward, he heals your pokémon and gives you the Dark-type Z-Crystal. You also get a new stamp for your Trainer Passport, which causes all pokémon up to level 65 to obey you.

Following a cutscene, you arrive in Aether Paradise.