Rhoda Brook lives alone with her son. Both have been abandoned by Farmer Lodge for a new wife, Gertrude. The play opens with Lodge arriving with Gertrude, much to the amusement of local people. That night, Rhoda has a dream in which Gertrude taunts the jealous Rhoda with her ring. Rhoda lashes out, grabbing Gertrude by the arm and flinging her across the room. A short time after the two women meet and, oblivious of Rhoda’s history (or the dream) Gertrude confides in the woman, showing her mysterious marks on her arm.
Over time the marks get worse and Gertrude’s arm begins to wither. She’s tried everything, to no avail. Desperate, she seeks Rhoda’s help in seeking out Conjuror Trendle, the local wise man. Trendle is unable to help Gertrude, but is able to show her who conjured up the spell – Rhoda.
Years pass by and Gertrude’s arm gets worse. Desperate, she once again seeks out Trendle who tells her that the only way of curing the affliction is to touch the neck of a newly hanged man. This will ‘turn’ the blood and cure the withered arm. Gertrude visits the local hangman who, after some hesitation, agrees to help her. The play ends with Gertrude touching the neck of a recently hanged youth. However, Farmer Lodge and Rhoda turn up. They are horrified that Gertrude should interrupt their grief in such a way – it’s Rhoda and Lodge’s son who has been hanged. Deep in shock, Gertrude dies.