Sakura Ogami recently discovered about whale island and noticed most of the students in hope's peak who went there never returned, so she snuck into pleasure island and noticed there's some options she can choose and is figuring out what she can do to find clues. It's up to you to help Sakura find out the mysteries of the island and if you make the wrong move, Sakura will become a sea animal, probably a whale, lol. Anyways, you gotta be careful about the options you make because it can lead to different consequences, so try to get a good ending, okay?
Here's some info about sea island:
Sea island is very huge so you might get lost if you don't have a map, there's also a lot of water in that area and you will witness sea creatures (which may or not be the victims of sea island)
Remember you decide her fate. Good luck!