At last, all will be known . . .
Many years have passed since Breeze Tinkerman vanished in her spring-powered plane over the northern Wastes while searching for the fabled lost city in the ice, but her daughter River is more than happy to carry on her legacy. The Vangar overlords have turned Astatia into a slave state, forcing citizens to work in their mines and factories, stealing Astatia’s resources for their own greedy ends while living safely high above in the sky-city known as Juntavar.
River has never known any life other than the mean streets of Dockside, but street life has made her strong and resourceful. She’s the perfect leader, and that’s what her ragtag group of rebels needs most. The rebels meet to conspire against their overlords but their meeting is interrupted by three sentinels-Vangar warriors whose bodies have been melded with nine-foot-tall suits of armor powered by steam-and River has no choice but to lead the Vangars away from the others, exposing her and forcing her to go on the run.
Along the way, River runs into some of the last people she’d ever expected to meet. She learns that there still might be a way to defeat the Vangars. She also learns that her mother’s fate may have been decidedly different than what she was led to believe. Now, River will do anything to learn the truth about her blood-kin. And one way or another, she’s determined to destroy the Vangars once and for all.

Breeze is an outcast, a half-breed orphan born into a world torn apart by a thousand years of war. Breeze never knew her elven mother, and when her human father is recalled to the war, he leaves her in the safest place he knows: in the care of a reclusive tinker.
The Tinkerman’s inventions are frightening at first-noisy, smelly, dangerous machines with no practical use-but when the war comes home, Breeze sees an opportunity. If she can pull it off, she’ll change the world forever. If she fails, she’ll be considered a traitor by both lands and will be hunted to her death.

Steam technology and spring-powered engines have evolved since the discovery of Blackrock Steel, which can store vast amounts of energy, but word of this incredible resource has spread far and wide. When a horde of barbarian warriors known as Vangars sweep across the Frigid Sea in massive airships fueled by precious but dwindling supplies of black tar-like oil, they are determined to learn the secrets of Blackrock Steel at any cost. They assault the capital city, slaying King Ryshan and the entire royal family, and then ravage the countryside, leaving a cloud of acrid black smoke and the stench of death in their wake.
Breeze has been content with the peaceful life of a pilot, shuttling nobles back and forth in her spring-powered planes for years, but now the kingdom of Astatia has once again been thrust into war. The Vangars have taken Tinker captive and Breeze must rescue the clever old inventor who has been a father to her for most of her life, but she has one chance to defeat the Vangars. If she chooses to save Tinker instead, Breeze might lose that opportunity forever.
In the midst of the chaos, Breeze finds herself trapped in the middle of a romantic conspiracy to wed her off to a young pilot. She has no interest in marrying her would-be suitor, nor in the young Tal’mar warrior who would claim her as his own . . . or does she? The only thing Breeze knows for sure is that if she fails, the secret of Blackrock Steel will fall into the hands of the Vangars and Astatia will face a dark future of slavery and ruin.