They attacked those boats, steal their treasures and usually buried the treasures in some distant island. After that, they would make a map with coordinates of the location of the treasure. It happens very often, after many years someone to find the map and look for the place signed on the map as a possible place of the treasure but the pirates thought about that too. They usually putted the cross on a wrong place but they knew that, so only they were able to find the treasure.
The pirate Jack, floating through the restless ocean waters, saw an island that is not signed on the map so he called this island a mystery island. Knowing how pirates do, the anchored the boat on that island, hoping that someone may buried his treasure there. Help pirate Jack explore the island and perhaps find something valuable.