York, 1369. Plague has returned to the city, and a series of deaths at St Leonard's Hospital is dismissed as part of the renewed pestilence. The hospital is burdened by debt and theft, however, and its master fears that scandal will destroy both the institution and his own career, prompting him to ask Owen Archer for an inquiry.
Owen is reluctant to leave Lucie coping with frightened patients and demands for remedies, especially when the victims seem to share little beyond their connection to the hospital. Careful questioning uncovers a second puzzle hidden within the deaths and suggests that someone is using epidemic confusion to conceal fraud and murder.