The IronHeart Chronicles Series by Allison Pang

In the slums of BrightStone, Moon Children are worth less than the scrap they must collect to survive. It doesn't matter that these abandoned half-breeds are part-Meridian with their ancestors hailing from the technologically advanced city that floats above the once-thriving, now plague-ridden BrightStone. Instead they are rejected by both their ancestral societies and forced to live on the outskirts of civilization, joining clans simply to stay alive... moreIn the slums of BrightStone, Moon Children are worth less than the scrap they must collect to survive. It doesn't matter that these abandoned half-breeds are part-Meridian with their ancestors hailing from the technologically advanced city that floats above the once-thriving, now plague-ridden BrightStone. Instead they are rejected by both their ancestral societies and forced to live on the outskirts of civilization, joining clans simply to stay alive. Not to mention their role as Tithe, leading the city's infected citizens deep into the Pits where their disease can be controlled.Nineteen-year-old Raggy Maggy is no different, despite the mysterious heart-shaped panel that covers her chest. Or at least she wasn't... Not until her chance discovery of a Meridian-built clockwork dragon--and its murdered owner. When the Inquestors policing the city find Maggy at the scene of the crime, she quickly turns into their prime suspect. Now she's all anyone can talk about. Even her clan leader turns his back on her, leading her to rely on an exiled doctor and a clanless Moon Child named Ghost to keep her hidden. In return, all she has to do is help them find a cure for the plague they believe was not exactly accidental. Yet doing so might mean risking more than just her life. It also might be the only key to uncovering the truth about the parents--and the past--she knows nothing about. less

When the worst of her nightmares finally comes to pass, Raggy Maggy finds herself in the depths of the Pits, an underground labyrinth of caves filled with Rotters, lost Meridians, and forgotten Moon Children. Injured and desperate, Maggy is swept into the machinations of a secret Meridian team of scientists stationed in the Pits, who have been charged with finding a cure for the Rot... moreWhen the worst of her nightmares finally comes to pass, Raggy Maggy finds herself in the depths of the Pits, an underground labyrinth of caves filled with Rotters, lost Meridians, and forgotten Moon Children. Injured and desperate, Maggy is swept into the machinations of a secret Meridian team of scientists stationed in the Pits, who have been charged with finding a cure for the Rot. But even as they patch her up, something doesn't feel right, and she soon discovers that their true goal may be something far more sinister.All Maggy can do now is break free of the scientists' compound and hope she can find a way out of the Pits...until she comes across a small group of other escaped Moon Children. Together, they search for evidence to prove that the Rot is part of a greater conspiracy, forging strange alliances and unlikely friendships along the way. But when tragedy strikes and a terrible plot is revealed, Maggy's call to action leads her to an old friend and the chance to unlock the secrets of her iron heart, and quite possibly, the very secret of Meridion itself. less