Ellen and May's father died some time ago, and May has started living in the family's broken-down, bug-infested cabin. While visiting, Ellen discovers that her sister has a handsome new lover named Peter and that May is due to give birth but has been enduring severe abdominal pains. Peter seduces Ellen, who has always been competitive with May (but has long denied it). Both the truth about Peter and his reason for seducing Ellen soon become clear.