You were on an adventure with your friends to find a hidden castle, the castle was in the middle of the island so you need to use a ship to go there. Your captain also already told you to ignore everything that happens once you're on a sail.

But tonight, your tropes decided to stop by the beach, everyone is asleep except you. So you go out and sit on the beach looking at the ocean at night, but suddenly you hear a melody, it sounds sweet but is actually mysterious.