Heart of Iron Books in Order

The Heart of Iron books are Ashley Poston's big, fast-moving YA space opera. The series throws together smugglers, royal politics, illegal androids, and ancient dangers, then asks a crew of young people to survive all of it with their hearts mostly intact. At the center is Ana, a teenage outlaw who was found drifting through space as a child and raised by a hard-edged captain and the crew she now calls family.

In Heart of Iron, Ana's first goal is simple and personal: save D09, the sentient android who has always been her safest place in the galaxy. Once he starts glitching, she goes chasing answers and lands in a larger fight over lost coordinates, dangerous secrets, and a kingdom that would rather see some people dead than free. The book moves with the energy of a chase story, but it always keeps one eye on loyalty, identity, and the cost of choosing your own future.

Found family is the engine here.

Soul of Stars picks up with the stakes turned all the way up. Ana is thought dead after escaping the HIVE, and now she has to find a way to save Di, take back her kingdom, and stop something even worse from swallowing her world. The sequel leans harder into the ensemble, especially the bonds and tensions inside the crew, while pushing them across the most dangerous corners of the Iron Kingdom. There is still romance, but it sits beside grief, sacrifice, and some truly bad odds.

What makes this duology work is the mix of scale and feeling. You get space battles, political danger, shifting alliances, and a looming ancient threat, but the books never lose sight of the people in the middle of it. Ana is stubborn and brave in a messy, human way. The rest of the crew each carry their own wounds, secrets, and hopes, which gives the story more warmth than a pure action series might have.

These books are best read back to back. The first opens the door to the world, and the second pays off the larger arc with more danger, more emotion, and a bigger sense of just how much this crew means to one another.

Come for the space chaos, stay for the crew.