Lucius, Quin and Isi are out to prove that the emperor Titus was murdered on the orders of their mortal enemy, Marcus Acilius Glabrio. Their quest for evidence drives them to enlist as legionaries on one of the wildest frontiers of the Roman empire: the rugged, windswept island of Britannia, home to the fierce and fearless Caledonians. Who can they trust in this lawless world of spies and back-stabbers? Can they find the proof they need, before Glabrio’s henchmen catch up with them?