Kaliope Dearborne, a customer service nobody for a pharmaceutical mega-conglomerate, wants only to escape her cubicle and find true meaning for her life. But after accidentally killing her little sister's bully, she's taken captive by The Warren, a ragtag group of runaway medical test subjects.

Kaliope learns that she and her captors are experiments owned by the VyroGen corporation. Locked away and evolving, pieces of her slough off as she grows stronger, faster, and hungrier. Only Thresher-not quite man, not quite animal-keeps her from losing her grip on reality.

When Kaliope discovers the hidden truth of her genetic code, she joins The Warren in the war against VyroGen. With chemistry-altering pheromones and brain-tampering, she's converted into a sleeper agent. But deep inside the dark heart of the corporation, Kaliope finds something that drastically changes her role in the war. She might win back her memories, her body, and her life, but will Kaliope lose her humanity in the process?