Within the space of an hour or two the dead bodies of two elderly ladies, Miss Sophia Carew and Mrs. Westmacott, were discovered in the vicinity of the town of Buddington-on-the-Hill; both women had been very recently murdered; death in each case had been caused by strangulation; each was found lying at full length clasping in her hands the stem of a Madonna lily. As far as anyone knew there was no connection between the two women; they had never met each other; although both were well-to-do there was no evidence that a beneficiary from the will of one could expect any benefit from the will of the other.

The work of a maniac? Could there be two murderers planning together their foul deeds? It falls to Carolus Deene, the inimitable schoolmaster—who was supposed to be taking it easy, recuperating from a severe attack of jaundice—to unravel the knot of mystery and prove himself once again a master detective.