1793, the West Country. Constable Oastler has been transferred to Bath, a spa town with curative waters and a reputation for recreation as well as recovery. Against a backdrop of elegant dances in the Assembly Rooms, underhanded dealings in Avon Street and a string of unnerving lectures in the ancient Roman Baths, two suspicious deaths occur. It's Spring but the Runner from Bow Street had better not be counting on a holiday.