Walkthrough: As you walk through Hau'oli City, you will be called to head to the Hau'oli City Marina where Team Skull is causing trouble. Once you reach the Marina, you will see Captain Ilima preventing them from stealing Pokemon. However, he will ask for your helping in defeating them. Afterward, he himself will challenge you to a Battle to test your strength (his Smeargle will have a move your Starter Pokemon is weak to).
Trainers:
Team Skull Grunt - Level 8 Zubat
Captain Ilima - Level 9 Yungoos, Level 10 Smeargle
Items:
X Defense - From Woman Near Terminal
X Attack - From Man Near Terminal
Super Potion - On Deck
Fresh Water (Vending Machine)