Very carefully she twisted her body sideways, intending to retrace her steps, but in an instant the sight of the surging waters—­miles and miles below, as it seemed—­sent her crouching to the ground.  She could not go back!  She felt as though her limbs were paralysed, and she knew that if she attempted to descend some incalculable force would drive her straight over the edge, hurtling helplessly to the foot of those rugged cliffs.

For a moment she closed her eyes.  Only by dogged force of will could she even retain her present position, half crouching, half lying on the ill-matched steps.  It almost seemed as though some power were drawing her, compelling her to relax her muscles and slide down, down into those awful depths.  Then the memory of a half-caught phrase she had overheard flashed across her mind:  “If you feel giddy, always look up, not down.”  As though in obedience to some inner voice, she opened her eyes and looked up to where, only a few battered steps above, she could see the door of the castle.

If she could only make it!  Rising cautiously to her knees she crawled up one more step and rested a moment, digging her fingers into the crevices of the rock and finding a precarious foothold against a projecting ledge.  Keeping her eyes fixed upon the door she scrambled up a few inches further, then paused again, exhausted with the strain.

Two more steps remained.  Two more desperate efforts, while she fought the hideous temptation to look downwards.  For an instant she almost lost all knowledge of what she was doing.  Guided only by instinct—­the instinct of self-preservation—­her eyes still straining painfully in that enforced upward gaze, she at last reached the door.

With a strangled sob of relief she knelt up against it and inserted the big iron key, with numbed fingers turning it in the lock.  The heavy door opened, and Nan clung to it with both hands till it had swung back sufficiently to admit her.  Then, from the security of the castle itself, she pushed it to and locked it on the inside, as the old woman at the cottage had bidden her, thrusting the key into the pocket of her sports coat.

She was safe!  Around her were the walls of the ancient castle—­walls that seemed almost part of the solid rock itself standing betwixt her and that horrible abyss below! . . .  Her limbs gave way suddenly and she toppled over in a dead faint, lying in a little crumpled heap at the foot of the wall.

It was very quiet up there within King Arthur’s Castle.  The tourists who, mayhap, had visited it earlier in the day were gone; no one would come again to-night to disturb the supreme stillness.  The wan cry of the gulls drifted eerily across the sea.  Once an enquiring sheep approached the slim young body lying there, stirless and inert, and sniffed at it, then moved away again and lay down to chew the cud.

The golden disc of the sun dropped steadily lower in the sky. . . .