A planet invaded by an alien race whose only imperative is expansion. They employed an analogue of their own DNA to destroy existing life on Vertara and alter the environment to prepare it for their arrival. But one of their programmed creatures goes awry and provides an opening for the planet’s defensive system to exploit. The exploi-tation takes the form of Ferona, who appears to join Jahoro in a quest that his engineered DNA has compelled him to undertake.