Complex sentence: After Jessie, James, and Meowth finally are accepted as members of Team Rocket, they go out to steal Pokémon, their main goal to steal Ash Ketchum's Pikachu.
Split into simpler sentences: After Jessie, James, and Meowth finally are accepted as members of Team Rocket, they go out to steal Pokémon. Their main goal to steal Ash Ketchum's Pikachu.