Lucas started in the Kanto region. He collected all the badges and defeated Team Rocket. He then beat the Kanto Elite Four and his rival, of the Kanto region, to claim the title of Champion of Kanto.
Three years later, he moved to Johto, or more specifically the quiet town of New Bark Town. He met his new jerky rival who didn't treat Pokemon nicely, Marcus. He then beat all the Gym Leaders there, and the new Kanto Elite Four, and the champion Lance. Lucas then proceed to go to Mt. Silver to train.
Team Rocket angry at Lucas beating them twice came up with a plan. They would use Celebi, the master of time, to send Lucas back in time, and deposit him in the far away region of Hoenn. After Lucas beat a girl named Kris, though everyone called her Lyra for some reason, Team Rocket sent there plan into action. Lucas was sent back in time and a kind woman from Littleroot Town found him unconscious on Route 101. She took him home and gave him new clean clothes. He then went on a journey in this region beating new evil teams, Team Aqua and Team Magma. He then beat this league and went to his original region of Kanto.
Sevii Islands Arc:
Lucas when he returned home
Lucas returned to the Kanto region, and his mom, which he forgot, ran up to him crying. Seeing his mom jogged his memory and he wanted revenge on Team Rocket for what he did to his mom. His mom gave him new clothes, Running Shoes, and a Rainbow Pass since she heard that Team Rocket was working in the Sevii Islands. He beat another division of Team Rocket in the Sevii Islands and then he learnt that another evil team in a far away region, called Sinnoh, was working with Team Rocket.
Lucas went to Twinleaf Town, and paid rent to a nice lady only charging him 100 pokedollars a month. His annoying neighbor, Jun, kept buging him, and wanted to become a trainer like him. Lucas traveled all around Sinnoh, avoiding annoying Pokemon like Bidoof, working on his love relationship, and trying to stay alive since Team Galactic is insane! Lucas beat Team Galactic, got all the badges, and defeated the Elite Four. He then learnt of another Team Rocket subdivision in a region near Kanto, Orre.
Lucas went to the Orre region to defeat Cipher, a subdivision of Team Rocket bent on making Shadow Pokemon, Pokemon that has there heart's artificiality shut to make them extremely powerful. Lucas caught all the Shadow Pokemon, purified them, and made best friends with a cool guy named Mirror B.. Then Lucas got angry when he learned that there is no Gyms here or an Elite Four, and is packing his bags to get ready to face Team Rocket head on again in the Kanto region.
Mystery Dungeon Arc:
Lucas was heading to Kanto on boat, and saw Team Rocket. Team Rocket had a laser pointing at him, and he tried to flee, but the laser beam hit him. Team Rocket took him, and deposited him in a far away region. He woke up on a beach, and saw a talking Charmander. The Charmander thought that Lucas was crazy after he had told him that he was a human not a Pikachu, but afraid about his own life he said that he thought he was a human. He made a team that he had called Team Rocket at the guild. He meet one of his old Pokémon saying that they were separated when they went back in time. He had then beat Primal Dialga, and then returned to the normal world, and kicked Team Rocket Admin Archer butt.
Future Kanto Arc:
Lucas, 14, got back to Kanto, and landed in Vermilion City. He was wanting a relaxing cruise after what Team Rocket had done, but he had to find some guy's daughter that he let run off! Lucas beat the gym leaders and fixed the Magnet Train. Lucas had then went home to see his mom. That he hadn't seen in a while.