Charlotte Blackburn - legend, traitor, the order's worst nightmare - she escaped the torturous experiments by the villainous Viceroy Arecibo, but is forever changed. Now, she battles to retain her humanity as she fights to survive among the wild sky settlers of Outer City. But an old threat emerges, and Charlotte must choose between revenge and redemption.

Ashton Wells has one purpose: Stop Europe's coalition forces from slaughtering the citizens of the peaceful union to prevent the spread of the trembling sickness. But his plan to overthrow the order from within is thwarted at every turn by his ex-love, Charlotte Blackburn. A woman he betrayed. His treachery resulted in her capture and now she will stop at nothing to destroy the order even if it means all-out war with Ashton.

Hunted by the brutal Viceroy and struggling to regain memories of the past two years wiped by the order, Charlotte must fight to master the devices and startling abilities thrust upon her as a result of her capture. As Charlotte and Ashton endeavor to discover the real reason for what was done to her, they uncover an unfathomable plan against the most innocent of Outer City's citizens.

With ruthless enemies mounting against the struggling citizens of Outer City, Charlotte must brave the terrors of the churning sea and face her darkest truth to retrieve a strange submersible machine - a device that may very well be humanity's last hope of survival.