In the third scene the plan of wild justice is formulated. It had originated in the mind of Owain, who had fed his brooding temper on old stories of revenge. To him the dreadful logic of the scheme seemed unanswerable. No power on earth or heaven could help them; either they must save themselves, or be destroyed, body and soul. He puts his plan before Shonnin--to lure their father by a light wrongly placed, as he rows home at night, on to the quicksands at the other side of the island. But Shonnin, if he has less strength of will than Owain, is more thoughtful and more sensitive. He is appalled at the proposal. Owain reminds him of their wrongs; asks him what this monster has done that he should live to be their ruin. And Shonnin, seeing the issues more clearly, replies ... Nothing; But then I have done nothing to deserve To be made a parricide. But Nelto has been listening, and hers is a nature of a very different mettle. Besides, as she has put the alternative to herself, it means but a choice between two evils; and this plan of Owain's seems at least a cleaner thing than the existence she had contemplated. She declares that she will be the instrument of the revenge. The rest of the play is occupied with the execution of the plan. Scene IV shows us Nelto going on her way down to the sea at night with the lantern that is to lead Gwyllim on to the sands. She is trying not to think; but the very face of nature seems to reflect the horror that is in her soul-- ... Down slips the moon. NELTO. Broken and tarnished too? Now she hangs motionless As 'twere amazed, in a silver strait of sky Between the long black cloud and the long black sea; The sea crawls like a snake. The figure of a woman suddenly appears in the path. It is her mother; she has overheard their plans, and for a moment Nelto is afraid that she has come to frustrate them. But Mrs Gwyllim has a very different purpose: she intends to take upon herself the crime that her children are about to commit-- All's fallen from me now But naked motherhood. What! Shall a hare Turn on the red-jawed dogs, being a mother, The unpitying lioness suckle her whelps Smeared with her heart's blood, this one law be stamped For ever on the imperishable stuff Of our mortality, and I, I only, Forbidden to obey it? But Nelto sees that she is too frail and weak for the task; and entreats her mother to return to the house. Time is slipping, and her father is waiting for the boat. MRS. GWYLLIM. Ellen, you are too young; You should be innocent-- NELTO. Never again After this night. Come, mother, I am yours; Make me a wanton or an avenger. MRS. GWYLLIM. Powers That set my spirit to swing on such a thread Over mere blackness, teach me now to guide it! NELTO. Mother, the moon dips.