"Welcome. Welcome, Edward Sedgley, to the Holy Planet!" This greeting marks the start of a mission that snatches one theoretical physicist from the relative comfort of academic life to be trained as one of the Guardians, extra-terrestrial beings responsible for the stability of the universe. He and his fellow student, Rabyd, metamorphose into a single entity, Tresargus, which is instrumental in preventing the invasion of earth by the Zetoids, an alien life form bent on universal expansion and domination. His former friends and colleagues are caught up in the conflict, each with a major role to play, and even after the Zetoids are defeated, a greater battle awaits them. Their universe is but one of many and now the entire Multiverse is threatened with destruction by a rogue universe. Together with Borel and Perigon, the last two surviving Zetoids, Ruth and Paul follow a similar journey to Edward's. The Guardians send them to the Philia, higher beings responsible for the Multiverse. What they learn challenges everything they believe and understand and they each respond in different ways - Borel is destroyed and Ruth escapes to follow her own path leaving Tresargus, Paul and Perigon to infiltrate and attack the rogue universe. Andy and Mary remain on Earth trying to rebuild their shattered civilisation aware that humans must atone for the destruction they have wrought on their world. A new civilisation will evolve but only if the Multiverse itself can be saved...