The battle between Ash and Kukui rages on. With Ash being the Alola League Champion and Kukui being the Professor of the region known for his battling skill, the battle could go either way and with Kukui bringing in Pokémon from all around the world, Ash faces a tough challenge, especially when Kukui sends in Venusaur against Ash's Rowlet. Will Ash be able to push through?

With Professor Kukui down to his final Pokémon, the Island Guardian of Melemele Island, Tapu Koko, intervenes and requests to be Kukui's final Pokémon in order to battle Ash. Ash, with Naganadel and Pikachu remaining faces one of the toughest battles he has ever had. Will Ash manage to break through and defeat the Island Guardian?