So he set out through the lonely valleys, and the first thing he saw was the greyhound lying dead, and he put her on his shoulder and would not leave her because of the love he had for her. And after a while he met with a cowherd, and he asked him did he see a woman going the way. "I saw a woman early in the morning of yesterday, and she walking hard," said the cowherd. "What way was she going?" said Diarmuid. "Down that path below to the strand, and I saw her no more after that," he said.
So he followed the path she took down to the strand till he could go no farther, and then he saw a ship, and he leaned on the handle of his spear and made a light leap on to the ship, and it went on till it came to land, and then he got out and lay down on the side of a hill and fell asleep, and when he awoke there was no ship to be seen. "It is a pity for me to be here," he said, "for I see no way of getting from it again."
But after a while he saw a boat coming, and a man in the boat rowing it, and he went down and got into the boat, and brought the greyhound with him. And the boat went out over the sea, and then down below it; and Diarmuid, when he went down, found himself on a plain. And he went walking along it, and it was not long before he met with a drop of blood. He took it up and put it in a napkin. "It is the greyhound lost this," he said. And after a while he met with another drop of blood, and then with a third, and he put them in the napkin. And after that again he saw a woman, and she gathering rushes as if she had lost her wits.
He went towards her and asked her what news had she. "I cannot tell it till I gather the rushes," she said. "Be telling it while you are gathering them," said Diarmuid. "There is great haste on me," she said. "What is this place where we are?" said Diarmuid. "It is Land-under-Wave," said she. "And what use have you for the rushes when they are gathered?" "The daughter of King Under-Wave is come home," she said, "and she was for seven years under enchantment, and there is sickness on her now, and all the physicians are gathered together and none of them can do her any good, and a bed of rushes is what she finds the wholesomest." "Will you show me where the king's daughter is?" said Diarmuid. "I will do that," said the woman; "I will put you in the sheaf of rushes, and I will put the rushes under you and over you, and I will carry you to her on my back." "That is a thing you cannot do," said Diarmuid. But she put the rushes about him, and lifted him on her back, and when she got to the room she let down the bundle. "O come here to me," said the daughter of King Under-Wave, and Diarmuid went over to her, and they took one another's hands, and were very joyful at that meeting. "Three parts of my sickness is gone from me now," she said then; "but I am not well yet, and I never will be, for every time I thought of you, Diarmuid, on my journey, I lost a drop of the blood of my heart." "I have got those three drops here in this napkin," said Diarmuid, "and take them now in a drink and you will be healed of your sickness." "They would do nothing for me," she said, "since I have not the one thing in the world that I want, and that is the thing I will never get," she said. "What thing is that?" said Diarmuid. "It is the thing you will never get, nor any man in the world," she said, "for it is a long time they have failed to get it." "If it is in any place on the whole ridge of the world I will get it," said Diarmuid. "It is three draughts from the cup of the King of Magh an Ionganaidh, the Plain of Wonder," she said, "and no man ever got it or ever will get it." "Tell me where that cup is to be found," said Diarmuid, "for there are not as many men as will keep it from me on the whole ridge of the world." "That country is not far from the boundary of my father's country," she said; "but there is a little river between, and you would be sailing on that river in a ship, having the wind behind it, for a year and a day before you would reach to the Plain of Wonder."
Diarmuid set out then, and he came to the little river, and he was a good while walking beside it, and he saw no way to cross it. But at last he saw a low-sized, reddish man that was standing in the middle of the river. "You are in straits, Diarmuid, grandson of Duibhne," he said; "and come here and put your foot in the palm of my hand and I will bring you through." Diarmuid did as he bade him, and put his foot in the red man's palm, and he brought him across the river. "It is going to the King of the Plain of Wonder you are," he said, "to bring away his cup from him; and I myself will go with you."
They went on then till they came to the king's dun, and Diarmuid called out that the cup should be sent out to him, or else champions to fight with him should be sent out. It was not the cup was sent out, but twice eight hundred fighting men; and in three hours there was not one of them left to stand against him. Then twice nine hundred better fighters again were sent out against him, and within four hours there was not one of them left to stand against him. Then the king himself came out, and he stood in the great door, and he said: "Where did the man come from that has brought destruction on the whole of my kingdom?" "I will tell you that," said he; "I am Diarmuid, a man of the Fianna of Ireland." "It is a pity you not to have sent a messenger telling me that," said the king, "and I would not have spent my men upon you; for seven years before you were born it was put in the prophecy that you would come to destroy them. And what is it you are asking now?" he said. "It is the cup of healing from your own hand I am asking," said Diarmuid. "No man ever got that cup from me but yourself," said the king, "but it is easy for me to give it to you, whether or not there is healing in it."
Then the King of the Plain of Wonder gave Diarmuid the cup, and they parted from one another; and Diarmuid went on till he came to the river, and it was then he thought of the red man, that he had given no thought to while he was at the king's house. But he was there before him, and took his foot in the palm of his hand and brought him over the river. "I know where it is you are going, Diarmuid," he said then; "it is to heal the daughter of King Under-Wave that you have given your love to. And it is to a well I will give you the signs of you should go," he said, "and bring a share of the water of that well with you. And when you come where the woman is, it is what you have to do, to put that water in the cup, and one of the drops of blood in it, and she will drink it, and the same with the second drop and the third, and her sickness will be gone from her from that time. But there is another thing will be gone along with it," he said, "and that is the love you have for her."
"That will not go from me," said Diarmuid. "It will go from you," said the man; "and it will be best for you make no secret of it, for she will know, and the king will know, that you think no more of her then than of any other woman. And King Under-Wave will come to you," he said, "and will offer you great riches for healing his daughter. But take nothing from him," he said, "but ask only a ship to bring you home again to Ireland. And do you know who am I myself?" he said. "I do not know," said Diarmuid. "I am the messenger from beyond the world," he said; "and I came to your help because your own heart is hot to come to the help of another."
So Diarmuid did as he bade him, and he brought the water and the cup and the drops of blood to the woman, and she drank them, and at the third draught she was healed. And no sooner was she healed than the love he had for her was gone, and he turned away from her. "O Diarmuid," she said, "your love is gone from me." "O, it is gone indeed," said he.
Then there was music made in the whole place, and the lamenting was stopped, because of the healing of the king's daughter. And as to Diarmuid, he would take no reward and he would not stop there, but he asked for a ship to bring him home to Ireland, to Finn and the Fianna. And when he came where they were, there was a joyful welcome before him.