In the spring of the year 118, Gaius Petreius Ruso has been stationed in the Roman-occupied province of Britannia for nearly a year. After his long and reluctant investigation of the murders of a handful of local prostitutes, Ruso needs to get away, volunteering for a posting with the army in Britannia's deepest recesses. These hinterlands are the homeland of Ruso's slave, Tilla, who has scores of her own to settle there. Her tribespeople are fomenting a rebellion against Roman control, and her former lover is implicated in the grisly murder of a soldier. Ruso is appalled to find that Tilla is still spending time with the prime suspect. Worse, he is honor-bound to try to prove the man innocent--and the army wrong--by finding another culprit.