Lilith Iyapo has given birth to what looks like a normal human boy, Akin. But his genealogy is complicated and includes an alien race that rescued humanity from a devastating nuclear war. The price the Oankali exact is a high one - they are compelled to genetically merge their species with other races, drastically altering both in the process. On a rehabilitated Earth, this new race is emerging, living alongside the 'pure' humans who choose to resist the aliens and the salvation they offer. These resisters are sterilized so that they cannot reproduce the genetic defect that drives humanity to destroy itself. When the resisters kidnap young Akin, the Oankali choose to leave the child with his captors. Will Akin give the resisters back their fertility and freedom, even though they will only destroy themselves again?