As for the Black Abbot – He breathed a little more quickly when he thought of that terrifying appearance. Whoever it was – and that it was human he did not doubt – they would live to regret their interference. By the time they reached Horsham, the girl, drenched to the skin, cold and shivering, had got back a little of her balance. Her teeth were chattering, but not with fear. She was inclined to be garrulous, but he answered in monosyllables or not at all.

“I wonder I didn’t die,” she said. “I’ve never seen anything so perfectly horribly ghastly! Did you see the way his eyes glared? They looked as if they were alight, didn’t they, Fabe?”

“Fabrian,” he snapped.

“I never saw anything like it, not even in the pictures,” said Miss Wenner. “Couldn’t we have the hood up, Fabe – Fabrian?”

He stopped the car with a jerk, pulled up the hood and fastened it.

“What are you going to do?”

“I’m taking you home. We’ll make another attempt tomorrow night. By the way, how did you get that stone corner piece to turn?”

“I can’t tell you that, Fabrian,” she said firmly and truly. “That’s my only hold over you.”

“Don’t be stupid. You used a bodkin or something, didn’t you? I noticed there was a space between two stones which looked to be artificial.”

“A pair of scissors,” she said. “There’s an iron catch inside that slit – I only found it by accident.”

He knew all he wanted to know now; could dispense with her for the rest of the night, for ever, as it happened. He declined her invitation to come upstairs for a drink and no sooner was she out of sight than he was flying back into Sussex.

Halfway between Dorking and Leatherhead, his petrol gave out, and he had to wait on the charity of a passing motorist, and it was not a night when traffic was very thick. At last he found a Good Samaritan who gave him enough to take the machine to the nearest filling station, and at Dorking, with his tank replenished and a few extra tins against emergency, he went on confidently.

Two o’clock showed on the illuminated dial of his watch when he backed the car into the field and mounted the slope to the ruins. From here onward he moved noiselessly, one step at a time, stopping every few paces to listen. But there was no sign or sound of the masked man.

He found the corner of the tower, with his penknife pressed back the catch, and, pulling at the rough stone, the edges of which crumbled in his hand, he opened the door.

Stopping only to examine the upper chamber, he went slowly down the stairs, his pistol in one hand, his lamp in the other. There was no sign of the intruder, but –