Chapter 3: Kahuna Hala
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Part 3: Kahuna Hala
Head south to exit Verdant Cavern. Ilima will open the barriacde blocking Route 3 when you get outside. The professor will meet up with you and explain Z-Moves. Continue north onto Route 3 and take any path at the fork. You'll find a Heal Ball and a trainer on the upper route, and a Sharp Beak on the lower route. Enter into Melemele Meadow.
You'll find Lillie and be tasked to save Nebby. Go left for a Great Ball and go through the meadow onto a cliff for a Nest Ball. Hop off into the meadow to the north and continue in that direction to find Nebby. You'll then exit the meadow and battle with Hau again. He'll have a Lv. 13 Pikachu and a Lv. 14 starter. After defeating him and engaging in a dialogue with the professor and comapny, continue forward on Route 3.
Head left and speak to the man in the overalls to get a Soothe Bell. Continue south post another trainer and pick up the Super Potion. You can now go back north and face the Red Card trainer next to the bridge if you've defeated all the trainers along the route. He'll give you a Red Card for defeating him. Continue south picking up the berries under a tree and you'll arrive back on Route 1. Heal up if you need to, otherwise head left back to Iki Town. After some dialogue, head north and speak with Hala to challenge him to a battle.
Island Kahuna Hala specializes in fighting tpye Pokemon, so a good Flying or Psychic type shoud make quick work of him. He has a Lv. 14 Mankey, a Lv. 14 Makuhita, and a Lv. 15 Crabrawler. As long as you have a few Pokemon in the Lv. 14-16 range, you shouldn't have two much trouble with him. He will give you Fightinium Z and your Grand Trial will be complete. He'll also give you a Ride Pager that will let you ride Tauros whenever you want. The professor will then give you TM54 - False Swipe. Lillie will also ask if she can tag along with you on your adventure, and who could say no?