John Roe O'Neill is a molecular biologist who has the knowledge, and now the motivation, to devise and disseminate a genetically carried plague - a plague to which, like those that scourged mankind centuries ago, there is no antidote, but one that zeroes in, unerringly and fatally, on women.

As the world slowly recognizes the reality of peril, as its politicians and scientists strive desperately to save themselves and their society from the prospect of human extinction, so does Frank Herbert grapple with one of the great themes of contemporary life: the enormous dangers that lurk at the dark edges of science.