The last humans from the planet Snowglade have taken flight from the genocidal mechs aboard the spaceship Argo. As the shop hurtles toward the Galactic Center, hunger and desperation are taking their toll among the refugees, who are beginning to question the leadership of Captain Killeen. Convinced that his people's only hope of survival lies in the True Center of the galaxy, he is determined to find it, with a will bordering on obsession.

As the crew of the Argo, an even Killeen's own son Toby, find their faith in their captain's brilliance tested to the limit, Toby faces his own perilous journey into the unknown, into the mysterious of adulthood. Like the others in this Family of voyagers, Toby's spine contains microchip implants holding the memories - the legacy - of his race. But just as the technology is designed to save his people may tear Toby himself apart, so his father's desperate gamble to save the Argo may plunge the ship and its inhabitants into a cosmic fit of all-consuming fire.