Scarcely had she set forth, when the King awoke, and rising from his couch, saw at once that the scabbard of his sword was gone.  Then summoned he the whole household to his presence and inquired who had entered his chamber.  “Sir,” said the Abbess, “there has none been here save only your kinswoman, the Queen Morgan le Fay.  She, indeed, desired to look upon you since she might not abide your awakening.”  Then the King groaned aloud, saying, “It is my own kinswoman, the wife of my true knight, Sir Uriens, that would betray me.”  He bade Sir Ontzlake make ready to accompany him, and after courteous salutation to the Abbess and her nuns, together they rode forth by the path that Morgan le Fay had taken.

Fast they rode in pursuit, and presently they came to a cross where was a poor cowherd keeping watch over his few beasts, and of him they asked whether any had passed that way.  “Sirs,” said the peasant, “even now there rode past the cross a lady most lovely to look upon, and with her forty knights.”  Greatly the King marvelled how Queen Morgan le Fay had come by such a cavalcade, but nothing he doubted that it was she the cowherd had seen.  So thanking the poor man, the King, with Sir Ontzlake, rode on by the path that had been shown them, and presently, emerging from the forest, they were aware of a glittering company of horsemen winding through a wide plain that lay stretched before them.  On the instant, they put spurs to their horses and galloped as fast as they might in pursuit.

But, as it chanced, Queen Morgan le Fay looked back even as Arthur and Sir Ontzlake came forth from the forest, and seeing them, she knew at once that her theft had been discovered, and that she was pursued.  Straightway she bade her knights ride on till they should come to a narrow valley where lay many great stones; but as soon as they had left her, she herself rode, with all speed, to a mere hard by.  Sullen and still it lay, without even a ripple on its surface.  No animal ever drank of its waters nor bird sang by it, and it was so deep that none might ever plumb it.  And when the Queen had come to the brink, she dismounted.  From the folds of her dress she drew the scabbard, and waving it above her head, she cried, “Whatsoever becometh of me, King Arthur shall not have this scabbard.”  Then, whirling it with all her might, she flung it far into the mere.  The jewels glinted as the scabbard flashed through the air, then it clove the oily waters of the lake and sank, never again to be seen.

When it had vanished, Morgan le Fay mounted her horse again, and rode fast after her knights, for the King and Ontzlake were in hot pursuit, and sore she feared lest they should come up with her before she might reach the shelter of the Valley of Stones.  But she had rejoined her company of knights before the King had reached the narrow mouth of the valley.  Quickly she bade her men scatter among the boulders, and then, by her magic art, she turned them all, men and horses and herself too, into stones, that none might tell the one from the other.