In a ruined future, an extraordinary artefact from the past lies buried.

Everyone wants it. But why? What is it? And how can it save them all? For scavs Cass and Wilbur, slaving to dig it up, there are no answers. But when two strangers from another time turn up claiming to know about the lost relic, their world will change for ever. Six Days. If you thought you knew how the world began ... think again.