Head out east and you’ll see the Plasma Frigate! Hugh will run out of the cave and will greet you. A board leading from the beach to the Frigate will then be set down and Marlon will walk down it. It seems he snuck onto the ship! He will leave and allow you to take on the Frigate yourself.
Hugh will rush up onto the ship. Head up onto it yourself. The battling will begin immediately!
Trainer Battle: Team Plasma Grunt
After being defeated, the Grunts on the deck will flee. Now head to the very south end of the boat, on the eastern side. Move up the steps and at the end of the boat you’ll find TM67 - Retaliate . Head to the very north end of the ship, up the steps. You’ll find a Revive . Head back down the steps and move over to Hugh.
He will move through a doorway. Follow him in. You’ll come upon a male and female pair of Grunts (Awww, Team Plasma romance!). Move up to them and let the double battle ensue. Looks like you’re once again paired up with Hugh for this fight!
Hugh’s party will be as follows:
If Snivy was your starter
If Tepig was your starter
If Oshawott was your starter
Double Battle: Team Plasma Grunt and Team Plasma Grunt
Male Grunt’s party
Female Grunt’s party
Once defeated, the two Grunts will sprint from the room. Talk with Hugh then head out onto the deck. You’re going to be hurting by now, but very soon you can take advantage of some free healing, courtesy of Team Plasma. However if you’re desperate, feel free to splurge on Revives and healing items.