Sir Ogier was walking alone in a dark wood near a castle which the peasants believed was haunted, when suddenly he heard the most blood-curdling shrieks. Now Sir Ogier was a very brave knight and had proved his greatness in battles and single combats, but even his courage was sorely tried and he was half inclined to take to his heels. He soon thought better of it, however, and grasping Courtain, his singing sword, he cautiously entered the dark, half-ruined archway. Almost reeling with a terrible fear, he advanced into the inky blackness, falling over scattered debris, startled when he was hit in the face by a flying bat, but ever drawing nearer those agonizing shrieks and groans. Even his teeth chattered as he staggered to a door beneath which he saw a faint ribbon of light. He listened. Again those cries of anguish, followed by low, cruel laughter. He crashed against the door with all the weight of his tall body and his coat of mail. It burst open under the heavy and sudden impact and he saw four red devils with long tails and horns, and in the hands of each was an instrument of torture. Stretched on a rack was a suffering, groaning man; and in the corner a cowering, trembling child. Fury and hate blazing within him, he sprang into the room with drawn sword. Who was this tortured man? Who was the frightened child?

Sir Ogier could not have guessed, anymore than you could, who this child really was. In time, however, he found out, and as a result of his rescuing the frightened boy, some very surprising and wonderful things happened. Sir Ogier performed many other deeds of heroism. But always, wherever he went, he took with him the singing sword. What part did it play? Before you finish the story you will know. 

From the E. M. Hale Cadmus edition of the book