Once a glorious utopian city, now a bloody field chained in the farthest icy desert in the world.

Irongate, a floating city that traveled the world for decades, has fallen tragically into the depth of hell after immoral science practice has led the city into the creation of a new species, The Mooncallers.

The Mooncallers have engaged in a never-ending fight against the surviving humans for fifty years, the city's advanced mechanism is decaying in the face of the vicious intelligent monsters who are activated by fullmoon and the battle must end.

Abigail awakens in the stock prison of Irongate as a Mooncaller, unaware of what happened to her, she traces back her old memories in hope to become human again, but where does her loyalty belong?