Daniel Walker is the sole survivor of first contact, something the world will never let him forget. Despite the continuing threat of attacks from a hostile alien race, he leads an exploratory mission to a new world to establish it as a candidate for colonization. Though prepared to face the aliens again if necessary, Daniel never anticipates a far greater threat will come from an embittered nanotechnologist seeking to cure himself of a nanogen plague and redefine what it means to be human.