AD180: Quintus Suetonius and his stepson Manius are frumentarii, the Roman Empire's secretpolice. Dispatched to Britannia on a mission whose purpose is kept veiled from them, theyjoin forces with the formidable female spy Tita Amatia and find themselves embroiled in plot, counter-plot and assassination, unsure of either their allies or theirenemies.They journey from bustling, cosmopolitan, civilised Londinium tothe wild North - a hostile snowbound land.Besieged by an alliance of rebellious local tribes, surrounded byintrigue, assailed by matters of the heart and personal ambition,they become reluctant players in a struggle between a ruthlessimperial government and others seeking control of the Empire.