Journey into transcendence. But unknown to Castor and his new, unexpected ally on the Ark, there are traitors to the cause in their midst?namely the Ferrets, composed of Office of Naval Intelligence operative Veta Lopis and her young team of Spartan-IIIs, who have been infiltrating the Keepers to lay the groundwork for Castor's assassination. But with ONI's field operations now splintered and cut off by the Guardian threat, Veta's original mission has suddenly and dramatically escalated in scope. There's simply no choice or fallback plan?either the Ferrets somehow stop the Keepers or the galaxy faces an extinction-level event….