Marpleisaskedbyherlawyer,ChristianGilbranson,tovisithisstep-mother,CarrieLouiseSerrocold,anoldfriendofMissMarple's,athercountryestate.Carrie'shusband,Lewis,confidestoMissMarplethathesuspectssomeoneisslowlypoisoninghiswife,andwhenGilbransonvisitsthemansion,heismysteriouslymurdered.
