A story of a girl fighting to seek the truth in a world where civilization is being rebuilt after the apocalypse. This is a world of rigid social classes that cannot be crossed.
Under the rule of the Church and the army, people live peaceful yet unequal lives.
When her beloved older sister, the only person she had to rely on, is kidnapped during a terrorist attack, the peaceful life of Erika, a lower-class citizen, is shattered.
To find her sister, Erika enters the professional qualifiers for the game Chosen One and successfully obtains a pass to the Upper City.
But she is swept up in a conspiracy that has been in the making since the dawn of creation. Caught between the Church, the army, and a third-party faction, she catches a glimpse of the world's true nature.
War, betrayal, deception, bloodshed...
The world quietly rots in darkness, then is devoured by aberrant beasts.
Everyone is a pawn in the game of power.
To pursue her ideal world, the girl decides to break out of the game and become the one who moves the pieces!
