Suze is going to the aquarium with her childhood friend Lulu. But suddenly Lulu goes missing... Suze follows Lulu and wanders into the Aquarium of Fear. Then, a mysterious person calling himself "Retro" suddenly attacked him. Chris," the wife of the aquarium director, who helps Suzu to escape. Kitty," a girl who has been trapped in the aquarium for a long time. There is only one clue to escape... Become a creature of the aquarium And solve their "secrets"... Who is the traitor?