Army doctor Gaius Petreius Ruso is waiting for the gods to smile on him. But, on a posting to the hostile North of Britannia, he's in for a long wait. Not least because the locals have a new hero who likes to strap antlers to his head and scare the Romans silly, while Ruso's slave girl, Tilla, is stubbornly refusing to identify the culprit in a police line-up.

But when Ruso is waylaid at the Fort of Coria, where a fellow doctor has confessed to a grisly murder, it's a case of out of the cauldron and into the fire. With Tilla thrust outside the fort (and into the arms of a former lover), Ruso is landed not only with Doctor Thessalus's patients but also the tricky task of getting him to retract the confession. Something smells fishy about this murder - and Coria is miles from the sea ...

Ruso faces a nightmarish investigation - trailed by the secret police, hunted by the Stag Man and betrayed by Tilla, is it any wonder he's seeking solace in the rather-too-watery local beer?