Pokemon's latest iteration is finally rounding out the Alolan League tournament, and Ash has come a long way. Even surprisingly making it to the final match, he's now up against his rival Gladion for the honor of becoming the very first Alolan League champion. Ash's history with League challenges is spotty at best, and there's a very good chance Ash could end up becoming victorious in a league for the first time in the official canon of the video game franchise. He could very well get another island league victory like he did with the Orange Islands long ago.
That makes the wait for each new episode especially arduous, and thankfully now we have more details as to what's coming next. Pokemon Sun and Moon Episode 139 is titled "He's Born! The Alolan League Winner!" and the synopsis for it (as translated by @Arkeus88) reads as such, "The fierce battle between Ash and Gladion in the finals finally concludes!! A champion will be determined! For the first time in Alolan history! Will Ash win his first League?!"
There's a more detailed summary offered too, which dives into the battle itself in further detail, "Intense battles continue throughout the finals. One Pokemon on each side has been defeated, and a battle between Ash's Pikachu and Gladion's Zoroark begins. Ash and Gladion's skills as trainers can be said to be equal. Which of them will win?!"
If you haven't kept up with the current run of the anime, the much anticipated Alola League arc is almost at an end! You can check out the preview for the next episode of the series in the video below captured by Moetron News:
Pokemon the Series: Sun and Moon is described as such, "What starts as a summer vacation in the tropical Alola region turns into the next exciting chapter in Ash Ketchum’s quest to become a Pokémon Master! There’s plenty for Ash and Pikachu to explore in this sunny new region, with exciting new Pokémon to discover and interesting people to learn from along the way—including the cool Professor Kukui and the fun-loving Samson Oak.
More new faces will help guide Ash’s Alolan adventure, in the form of a group of skilled Trainers—Kiawe, Lana, Mallow, and Sophocles—and a mysterious research assistant called Lillie. Frequent foes Team Rocket have also made the trip to Alola, looking to swipe some high-powered new Pokémon. But they have some heavy competition on the villainy front: the ruffians of Team Skull, who delight in causing chaos and may have more sinister intentions..."