Alice is traveling with her archaeologist father, Professor Telesu. She has a Slowpoke that evolved into Slowking, named Arthur. Slowpoke ran away to help save the Slowpokes in Slowpoke from Team Rocket and then evolved into a Slowking while helping the other Slowpoke. After he evolved, he blasted away Team Rocket.
Arthur was Alice's Slowpoke, who traveled with her. Upon seeing the other Slowpoke and Slowbro weakened, it took the King's Rock and a Shellder bit it, causing Arthur to evolve into Slowking. It revealed a path to a cave, where it now resides with the Slowpoke as a leader.