It's a bit of the fakemon journey

You get your starter from a descendant of the island who comes to visit and ask you. To stop the other ships for claiming this land that right there no rival. You fight each ship captain for a coin to say that this is your land. But if you lose, they take the coins, and you have to fight them to get them back. The rest crew will fight you if you win they will give a piece of the map to their captain to face them. After you win, they can come after and try to get the coin back, so be careful and keep your pokemon hp healthy.