As with the previous three series, the XY series began with only Ash Ketchum, headed off to a new region with his Pikachu while wearing a new set of clothes. His previous companions, Iris and Cilan, left the series. Joining him this time are Serena, a new Trainer who previously met Ash in her childhood; Clemont, an aspiring inventor and scientist who is also the Gym Leader of the Lumiose Gym; and Bonnie, Clemont's younger sister. Jessie, James and Meowth continue to follow Ash and his friends through the Kalos region, and have gone back to their more traditional methods of capturing Ash's Pikachu and other Pokémon, although their appearances are less frequent, just like in the Best Wishes series. Jessie's Wobbuffet returns to her roster. This series also features a series of side story episodes following the adventures of a Trainer named Alain, who is working to find Mega Stones and defeat all Mega Evolutions using his Mega Charizard X. It is currently unknown how many seasons the series will be divided into for audiences outside of Japan.