Ruso and the DeMented Doctor

N.B. R S Downie is published in the US as Ruth Downie and this book, "Ruso and the Demented Doctor", is published in the US as "Terra Incognita". It's wind-swept North Britannia, where the natives are in the mood for killing ...Gaius Petreius Ruso, medicus to the Twentieth Legion, has been posted to the hostile north - and thrown into a no-win situation. Thessalus, the current doctor at the Fort of Coria, has confessed to a grisly murder and his Prefect demands Ruso take charge of the patients and convince Thessalus to retract his confession. Or else. It seems a reputation for solving tricky murders down south isn't always helpful. Unfortunately, the corpse is offering up few answers other than to suggest that the natives might be more murderous than restless. If Ruso is to identify the killer, he'll need all his wits about him to keep Romans, natives and slave girls from each other's throats.