En ny rival

A trainer named Gladion, dressed in black, battling with a powerful fiery-eyed Lycanroc and wearing a Z-ring, has appeared on Melemele Island. After seeing them in action, Ash naturally wants to battle Gladion; however, he's totally shocked when Lillie appears and calls Gladion her brother . Gladion seems cold towards Lillie and at first refuses Ash's challenge, but then learns that Ash got his Z-ring from Tapu Koko and had actually battled the Island Guardian. That night, Gladion's Umbreon delivers a note to Ash agreeing to battle. It's Ash's Rockruff versus Gladion's Lycanroc! However, Team Rocket, who saw Gladion defeat the Team Skull grunts earlier, can't resist getting involved . Ash and Gladion must work together to rescue Pikachu and Lycanroc.