Melody Keen is the first child born on Mars, where her family populates a research settlement. When Melody is two, the adults begin vanishing. Though they return minutes later, they are not completely human. Melody is left alone with aliens who are using the bodies of her family members as hosts.Arriving days later, the rescue team finds Melody alive, and her family dead. The Terrans learn little of the aliens; the traumatized child remembers nothing.Melody...