Pokémon the Series: Sun & Moon Episode 42: Alola, Kanto!
Episode 42 of 146 of Pokémon the Series: Sun & Moon, aired September 14, 2017, 25 minutes. Available with English subtitles and dub where released.
Episode summary
Ash’s Pokémon School class is taking a field trip to the Kanto region! Principal Oak is excited to visit his famous cousin in Pallet Town, and Professor Kukui says some special guests will be joining them. When those guests turn out to be Brock and Misty, Ash is delighted!