This is the cable that the diver carried from the Council Chamber, thought Raphael with sudden inspiration. Not knowing exactly what to do, the boy mounted the steps and hurried along a smooth concrete passageway which led directly into the castle itself. Forgetting the might and cunning of the enemy in his impatience, he ran, his feet pattering along the corridor like rain upon a shingle roof. Ahead of him lights blazed, but no one stopped him, no one appeared. He climbed a long flight of marble stairs, and so came through a door of brass into the great central hall of the castle. It was a huge semi-circular room like a cathedral apse, lined with winking elevator shafts that rose toward the distant ceiling in blazing piers of metal. Raphael hesitated for a moment and then followed the cable through an open door. The room into which he came was lined with rich imitation oak paneling, and contained a large mahogany-stained table. The cable ended here. In the center of this table rested a steel box japanned in black enamel. Halfway under the box lay a letter, thin and white, on the outside of which was printed in large letters _RAPHAEL_, and below this in writing, ‘_In the event of his discovering this dictaphone_.’ Raphael hastily tore open the letter, and read as follows: CASTLE OF THE SEA MY DEAR RAPHAEL: Through my dictaphone I have discovered your plot to destroy me and my castle. As I quite realize your ability to carry out your plans so conveniently outlined, I have made mine in advance. Cassandra and I leave in a moment by submarine for a safer retreat from your unwished-for attentions. I trust that this letter will relieve you of further search, my only regret being that our destination must be kept a secret from you. Give my respects to all your old-fashioned friends above and below. I remain Your humble And devoted servant MECHANUS P.S. Cassandra sends her love. Raphael stared at the letter a moment. Then he ran to the door, and back into the great hallway. Here he stopped and looked desperately about. It was almost impossible to go back. He thought of the roof, the roof and the eagles. All the elevator doors stood open. Raphael stepped into the nearest one and grasped the starting lever. Up, up he shot with dizzy speed. He wondered, as they passed floor after floor, how tall the castle was. Where should he stop? Perhaps the elevator would shatter itself against the roof and drop him down the long shaft. The car jarred and came to a sudden stop. Raphael jerked back the elevator door and stepped into a long corridor. Peering up between the landing and the cage, he saw the roof itself just above him. He was on the top floor.