Marple is asked by her lawyer, Christian Gilbranson, to visit his step-mother, Carrie Louise Se@美国特色一大片@rrocold, an old friend of Miss Marple's, at her country estate. Carrie's husband, Lewis, confides to Miss Marple that he suspects someone is slowly poisoning his wif@鹤乡文字网@e, and when Gilbranson visits the mansion, he is mysteriously murdered.