Bio-chemistry whiz Everly Jax wants one thing: to know who her parents are. Raised with other repo kids in InKubator 9, she has pinned her hopes on Reunion Day, the annual event where sixteen-year-olds can meet or reunite with their parents. When her Reunion Day goes horribly awry, she and her pregnant friend Halla escape the Kube, accompanied by their friend Wyck who has his own reasons for leaving. In a world where rebuilding the population is critical to national survival, the Pragmatist government licenses all human reproduction, and decides who can—and must—have babies. The trio face feral dog packs, swamp threats, locust swarms, bounty hunters looking for "breeders," and more dangers as they race to Amerada's capital to find Halla's soldier boyfriend before the Prags can repo her baby and force the girls into surrogacy service. An unexpected encounter with Bulrush, an Underground Railroad for women fleeing to Outposts with their unlicensed babies, puts them in greater peril than ever. Everly must decide what she is willing to sacrifice to learn her biological identity—and deal with the unanticipated consequences of her decisions.

After soldiers storm the Bulrush compound, Everly Jax spends four months in prison, uncertain of her friends' fates and determined to figure out who betrayed Bulrush. When she goes on trial for murder, her only hope is a mysterious lawyer who may not have her best interests at heart. After the stunning verdict, she's convinced she has been betrayed again. A daring rescue brings her to a Defiancé cell where she is overjoyed to find some of her friends alive. She's caught up in rebel operations until the locusts display a horrendous new adaptation. Realizing she's more valuable to Amerada in a lab than with the Defiancé, Everly returns to Atlanta under a new identity to become part of the locust eradication e ort . . . and spy for the Defiancé. On her own in Atlanta, she confronts an enemy from her past, makes a heart-rending discovery, and learns her parents' identities—which divides her loyalties still further.

After she escapes Atlanta, Everly Jax returns to the Defiancé cell in time to help capture Kube 9, her former home. There, she works feverishly with Dr. Ronan to recreate her locust eradication experiments. She is on the verge of success when an Infrastructure Protection Force general perpetrates an atrocity that leaves them all reeling. Suddenly unsure who she can trust, Everly finds her way to the Defiancé's secret headquarters, and discovers a surprising ally in the High Commander. Together with Minister Alden, they scramble to thwart a genocidal plan that threatens all the geneborns . . . including Saben. When the worst happens, Everly and her friends turn their efforts to mitigating the tragedy. A showdown at sea brings Everly face to face with the madman who hatched the genocide plot, and she must risk her life in an almost certainly futile attempt to save Amerada and her friends. The Incubation trilogy comes to a thrilling and surprising conclusion in Regeneration.