For centuries, the sea has engulfed this world. People that need to travel by boat go to islands, but be aware that there are numerous monsters in the sea, deep down there.

You were recently aboard your childhood friend's ship, Xinyan. She is the Great Swordsman Kazuha's sister, raised by Captain Beidou herself.

"Jee, jee, you haven't changed all that much, eh?" she says. You sat in her soundproofed music room while the ship shook.