Former governess Emma Betony is living in quiet and boring retirement when two unexpected letters arrive. The first is a lonely hearts magazine, with an entry ("Lonely Batchelor, age 49, good health, comfortable income, seeks friendship of unattached lady with view to matrimony") highlighted by the anonymous sender. The second is an appeal for help from a former student. Grace Aram is running Makeways, a struggling boarding school for girls, newly relocated to a site of former nursing home in Dorset. Grace isn't interested in Miss Betony's teaching skills-she wants a trusted friend to help identify the culprit behind a series of troubling events. Two nursing patients have remained at Makeways and one appears to be the victim of a poisoner. It is not clear who could be responsible for the ongoing trickle of arsenic found in Miss Thurloe's drinks- the new abrasive doctor, the pragmatic nurse, the nervous teaching staff or the high-strung students. During her investigations, Miss Betony uncovers an overwhelming sense of fear on the part of Makeways' inhabitants, and clues that lead to the Great Ambrosio, a charismatic fortune-teller, who seems to have an undue influence on various teachers, students - and Miss Thurloe.