There... There is a city below the surface. Thanks to stolen Teigu, a man called Andrew was able to create a city on the ocean floor. At first everything was going well but everyone know that a real utopia is just a fiction. People changed, became monsters fighting for ADAM. A single Big Daddy decided to ran away as his prority was protecting the assigned Little Sister which he looked at as his own daughter. What will reaching a surface change for the two, where war between Empire and Rebelion is ripping country apart?