Glasgow 1492. Gil Cunningham returns to his old university for the Nicholas Feast, where he and his colleagues are entertained by a play presented by some of the current students. One of the actors, William Irvine, is later found murdered. With the assistance of Alys, to whom Gil has recently become betrothed, Gil begins to disentangle a complex web of espionage and blackmail involving William's tutors and fellow students. Matters are further complicated by the arrival of Gil's formidable mother who is determined to inspect his betrothed. Little do Alys and Gil realize that it will be she who provides the final, vital key to unmask the murderer and unveil his motives.