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. . . .

"Nan's very late."

Mrs. Seymour made the statement rather blankly. Dinner had been announced and the house-party were gathered together in the hall round the great hearth fire. The summer day had chilled to a cool evening, as so often happens by the sea, and the ruddy flames diffused a cheery glow of warmth.

"Perhaps Lady Gertrude is keeping her to dinner," said Lord St. John.

"It's very probable." As he spoke he held out his hands to the fire--withered old hands that looked somehow frailer than their wont.

Kitty shook her head.

"No. She--I don't think she enjoyed her visit overmuch, and, when she came back she went out cycling--to 'work it off,'" she said.

"Where did she go?" inquired Penelope.

"To Tintagel. I told her she wouldn't have time enough to get there and back before dinner. Never mind. We'll begin, and I'll order something to be kept hot for her."

Accordingly they all adjourned to the dining-room and dinner proceeded in its usual leisurely fashion, although the gay chatter that generally accompanied it was absent. Everyone seemed conscious of a certain uneasiness.

"I wish young Nan would come back," remarked Barry at last, looking up abruptly from the fish he was dissecting. A shade of anxiety clouded his lazy blue eyes. "I hope she's not come a cropper down one of these confounded hills."

He voiced the restless feeling of suspense which was beginning to pervade the whole party.

"What time did she start, Kit?" he went on.

"About five o'clock, I should think, or soon after."

"Then she'd have had loads of time to get back by now."

The general tension took the form of a sudden silence. Then Peter Mallory spoke, very quietly:

"She didn't propose going up to the castle, did she?" In spite of its quietness his voice had a certain clipped sound that drove home the significance of his question.

"Yes, she did." Kitty tried to rea.s.sure herself. "But she's as surefooted as a deer. We all went up the other day and Nan was by far the best climber amongst us."

Almost simultaneously Peter and Barry were on their feet.

"Something may have happened, all the same," said Barry with concern.

"She might have sprained her ankle--or--or anything."

He turned to the servant nearest him.

"Tell Atkinson to get the car round and to be quick about it."

"Very good, sir." And the man disappeared on his errand.

In a moment the thought that a possible accident might have befallen Nan broke up the party. Kitty and Penelope hurried off in quest of rugs and sandwiches and brandy--anything that might be of service, while the men drew together, conversing in low voices while they waited for the car.

"You'll find her, Barry?" St. John's voice shook a little. "You'll bring her back safe?"

"I'll bring her back." Barry laid kindly hands on the old man's shoulders which had seemed suddenly to stoop as though beneath a burden. "Don't worry. I expect she's only had some trifling mishap.

Burst a tyre probably and is walking back."

St. John's look of acute anxiety relaxed a little.

"I hope so," he muttered, "I hope so."

A servant opened the door.

"The car's waiting, sir."

"Good." Barry strode into the hall, Mallory following him.

"Barry, I must go with you," he said hoa.r.s.ely.

In the blaze of the electric light the two men looked hard into each other's faces. Then Barry nodded.

"Right. I'll leave the chauffeur behind and drive myself. We must have plenty of room at the back in case Nan's hurt." He paused, then held out his hand. "I'm d.a.m.ned sorry, old man."

"I suppose Kitty told you?"

"Yes. She told me."

"I think I'm rather glad you know," said Peter simply.

Then, hurrying into their coats, the two men ran out to the car and a moment later they were tearing along the road, their headlights blazing like angry stars beneath the calm, sweet light of the moon overhead.

The old dame who kept the keys of the castle rose from her supper as the honk, honk of a motor-horn broke on her startled ears. People didn't come to visit the castle at this time of night! But the purr of the engine outside her cottage, and the long beams of light flung seawards by the headlights, brought her quickly to the door.

"We want a key--for the castle," shouted Barry, while to expedite matters Peter sprang out of the car and went to the floor of the cottage.

"The key!" he cried out.