When he reached the fountain where a silver cup hung by a silver chain, he filled the cup with water, as the troll had bidden him, and threw it over a pillar of stone that was set beside the fountain. And instantly there came a clap of thunder as if the earth would dash asunder, and after the thunder came the shower, and so fierce and heavy were the hailstones that they would surely have slain horse and rider, but that Sir Owen, as the troll had bidden him, had put his horse's forefeet in the fountain, and kept his own hand therein, whereby the hailstones became thin rain before they touched him. Then the sky became bright, and the flock of birds descended on the tree and began to sing. But Sir Owen heeded them not, but mounted his horse, dressed his shield and lance, and prepared for the combat. There came a mourning cry through the wood, and a sky-blue knight on a high-stepping destrier dashed through the trees towards Sir Owen, and came against him, lance in rest. Whereupon Sir Owen put spurs to his horse, and furiously rode against the knight. At the first onset each broke his lance; whereat they drew their swords and lashed at each other most fiercely. Sir Owen feinted, and then, quickly recovering, he smote the other so hard and stern a blow that the blade bit through headpiece, skin and bone, until it wounded the brain itself. Then, with a great cry, the blue knight wheeled his horse and fled, with Sir Owen in pursuit. But the other knight's horse was fleeter, and Sir Owen could not overtake him, though he kept within a few yards. In a little while a great castle, resplendent with new stone, shone before them. The wounded knight thundered across the drawbridge, with Owen close behind him; but when the blue knight gained the street beyond, the portcullis was let fall with a rush. Sir Owen fell from his horse, and looking round he found that the horse had been cut in twain by the gate. So that Sir Owen found himself, with the forepart of the dead horse, in a prison between the two gates, while the hinder part of the horse was outside. And Sir Owen saw that his death must be very near, for already he saw one of the soldiers who were guarding the gate run after the knight to the castle, as if for orders to slay him. Looking through the inner gate, he saw a narrow street facing him, with booths and little houses on each side; and coming towards him he beheld a maiden, small but beautiful, with black curling hair and a circlet of gold upon her forehead; and she was of high rank, for she wore a dress of yellow satin, and on her feet were shoes of speckled leather. She stopped when but a few steps from the gate where the soldiers stood watching Sir Owen; and he saw that her eyes were bent fixedly upon the blue stone which lay on the knight's breast. And he saw that, in the darkness of his prison, it shone with a fierce blue flame.