You swim in the deep ocean like you always do when you're bored. You like the underwater world, it always gives you a calm vibe.

Today you decided to swim deeper into the ocean and found a new world: A world of Mermaids. As you're about to swim deeper, you suddenly feel something hit your head, making you pass out on the spot. As you wake up, you find yourself in a big hall with heavy chains on your feet. As you look up, you meet Dazai's cold gaze while two guard-mermaids stand at his side.