Down he went as the horse desired, and he got the spikes made, and back he came with them. "Stick them into me," said the horse, "every spike of them in every bone end that I have." That he did; he stuck the spikes into the horse. "There is a loch here," said the horse, "four miles long and four miles wide, and when I go out into it the loch will take fire and blaze. If you see the Loch of Fire going out before the sun rises, expect me, and if not, go your way." Out went the black horse into the lake, and the lake became flame. Long was he stretched about the lake, beating his palms and roaring. Day came, and the loch did not go out. But at the hour when the sun was rising out of the water the lake went out. And the black horse rose in the middle of the water with one single spike in him, and the ring upon its end. He came on shore, and down he fell beside the loch. Then down went the rider. He got the ring, and he dragged the horse down to the side of a hill. He fell to sheltering him with his arms about him, and as the sun was rising he got better and better, till about midday, when he rose on his feet. "Mount," said the horse, "and let us be gone." He mounted on the black horse, and away they went. He reached the mountains, and he leaped the horse at the fire mountain and was on the top. From the mountain of fire he leaped to the mountain of ice, and from the mountain of ice to the mountain of snow. He put the mountains past him, and by morning he was in Realm Underwaves. "You are come," said the prince. "I am," said he. "That's true," said Prince Underwaves. "A king's son are you, but a son of success am I. We shall have no more mistakes and delays, but a wedding this time." "Go easy," said the Princess of the Greeks. "Your wedding is not so near as you think yet. Till you make a castle, I won't marry you. Not to your father's castle nor to your mother's will I go to dwell; but make me a castle for which your father's castle will not make washing water." "You rider of the black horse, make that," said Prince Underwaves, "before the morrow's sun rises." The lad went out to the horse and leaned his elbow on his neck and sighed, thinking that this castle never could be made for ever. "There never came a turn in my road yet that is easier for me to pass than this," said the black horse. The lad gave a glance from him and saw all that were there, and ever so many wrights and stone masons at work, and the castle was ready before the sun rose. He shouted at the Prince Underwaves, and he saw the castle. He tried to pluck out his eye, thinking that it was a false sight. "Son of King Underwaves," said the rider of the black horse, "don't think that you have a false sight; this is a true sight." "That's true," said the prince. "You are a son of success, but I am a son of success, too. There will be no more mistakes and delays, but a wedding now."