When a mysterious invitation arrives for the redoubtable Miss Phryne Fisher from an unknown retired Captain Herbert Spencer, Phryne's curiosity is piqued. Spencer runs a retreat in Victoria's rural spa country for shell-shocked veterans of World War I. It's a cause after Phryne's own heart, but what can Spencer want from her? Phryne and her faithful servant Dot set out for Daylesford, viewing their rural sojourn as a short holiday. But the pair barely have time to unpack before they are thrown into treacherous Highland gatherings, a mysterious case of disappearing women, and a string of murders committed under their very noses. With her usual pluck, deft thinking and several satisfying costume changes, Phryne methodically investigates the strange goings-on in this anything-but-tranquil spa town.