The riddle of St. Leonard's

Historical mystery novel set in medieval York. Fifth in the series featuring Owen Archer, the Archbishop's spy. The fetid summer heat of 1369 has the citizens of York besieging Owen Archer's apothecary wife, Lucie, for physicks against noxious vapors. But more than pestilence is in the air. Owen is summoned to investigate the theft of rare treasures from St. Leonard's Hospital and the untimely deaths of aging patients.