Someone was calling him. Peter could hear his name being spoken, but the voice was very far away. He became aware of a dull ache in his head, and opened his eyes with a groan. The voice sounded nearer; he identified it gradually as his sister's, and as the mist cleared from before his eyes he saw her face above him. Puzzled, he stared up at her. She was stroking his cheek. "Darling, you're better now, aren't you? Peter, speak to me, please speak to me!"

He blinked; his head was splitting, he thought. He said thickly: "Hullo… Margaret! What - what's happened?"

She appeared to be crying. "Oh, thank God!" she said. "I thought you were dead. Oh, my dear, how did he get you?"

He moved his head, staring round him. He was lying on a bare stone floor, in a queer cell-like room which he never remembered to have seen before. His brain felt clogged, but bit by bit his memory was returning. He struggled up on his elbow, grasping Margaret's wrist. "You called me!" he said. "I couldn't find you. Then I…' He broke off, as the whole scene came rushing back to him. "My God, where are we?" he said. "What happened to you?" He put his hand to his head feeling it tenderly. "Lord, my head! Something must have knocked me out. How did I get, here? How did you get here?"

She helped him to his feet. He was still feeling sick and dizzy, and was glad to sink down on to a chair by the plain deal table, and to rest his head in his hands. Margaret knelt beside him. "It was the Monk," she said.

"I heard you call," he said. "Couldn't find you. Then I saw your handkerchief."

"Where?" she asked.

"By the panel. Made me think. Realised there must be a way we hadn't found. Got on to the moulding. An apple. Did you twist it?"

"Yes, yes. By the fireplace. And then?"

"Saw the panel move. So anxious about you, like a fool never stopped to think. Dashed in. Shouted to you. Then…' He stopped, frowning. "Yes, I heard something behind me. I think I turned round. I don't remember anything else. What happened to you? How did you get here? Who brought me here?"

She glanced fearfully over her shoulder at the door of their prison. It was shut, but a steel grille at the height of a man's head was let into it. A sort of shutter with round holes cut in it was drawn across the grille on the outside. She turned back to Peter, and slid her hand into his. "When you'd gone I knelt down and lit the fire, Then I started to get up, and you know how you put out your hand to steady yourself? Well, I did that, and caught on to the apple in the carving. It moved, and I saw the opening in the wall, just as you did. I called you, but you'd gone. I never meant to go in, but there didn't seem to be anything there, and I did just step inside, holding on to the panel all the time. Peter, it was a staircase! Did you realise that?"

"Yes, I remember thinking in a flash how that was what Duval must have meant when he said the Monk went up and down the stairs though we didn't see. Go on: what happened next?"

She shuddered. "It was so awful… my bangle - you know the one - came undone, and fell on to the second step. I didn't stop to think: I never dreamed - anyone was there. I let go the panel and just stepped down one stair to pick it up." Her fingers clung suddenly to his hand. "Peter, I saw the light going, and I turned round, and the panel was closing! Peter! I nearly went mad! I couldn't stop it, and that's when I screamed. I tried to tear it open; it was pitch dark, and I couldn't see any catch, or feel anything. I shrieked for you again and again. Then - then I heard something moving." She was shaking like a leaf. He put his arm round her, clumsily patting her shoulder. "A sort of padding footstep, coming nearer and nearer. And I couldn't see, couldn't move that awful panel. Then - I felt something creep over my mouth. It felt horrible, horrible! Then I knew it was a hand in a glove. It gripped my face so that I could hardly breathe, and an arm grasped me round above the elbows. I couldn't move, I heard you call out to me from the library, and then - then, there was a fiendish sort of chuckle, quite soft, but so utterly wicked, and cruel, that it just finished me, and I fainted. When I came to I was in this place, quite alone. I didn't know how I got here, or who that hand belonged to - or - or how long I'd been here till the door opened, and I saw the Monk standing there. He didn't speak; he looked at me for a moment through those slits in his cowl, then he turned and bent down and started to drag something in. It was you, Peter, and oh, I thought you were dead, I thought you were dead! He just let you fall on the floor, and went out. I hadn't any water or anything to bring you to. I undid your collar, and when you didn't move, I was so desperate I shrieked for someone to come and at least let me have some water. But no one did and no one answered. Only this awful roaring noise went on."

He lifted his head. "Then there is a noise? It's not just in my head?"

"No, it's never stopped all the time I've been here."

He sat for a few minutes trying to collect his thoughts. "Poor kid!" he said. "Ghastly for you. And a fat lot of good I've been to you!"

She laid her cheek against his arm. "You're here, and that's all I care about. You don't know what it was like to be alone. At least we're together now."

"If only my head didn't ache so much I might be able to think," he said. He looked round, and blinked. "Where the hell are we?" he said. "Electric light?"

She glanced up at the bulb that had caught his attention. "So it is. I haven't had time to notice it till now. Then we can't be in the Priory, can we?"

He got up, and began to move round the small room. It was like a square cave cut out of solid stone, all except the door which was made of thick wood. "No window," he said. "We must be underground." He went to the door, and slipping his hand sideways between two of the bars of the grille, tried to push back the shutter by inserting a finger into one of the ventilation holes. He could not move it, nor could he manage to see anything through the holes.

"If we're underground that accounts for the coldness and the smell of damp," Margaret said. "Peter-you don't think - they're going to leave us here - to starve?"

"Of course not," he said instantly. He stood by the door, listening. "That noise," he said. "That's a machine and an electric one, or I've never heard one!" He stared across at his sister, dawning suspicion in his eyes. He seemed about to speak, then checked himself, and went up to one of the walls, and closely inspected the stone blocks that formed it. "I believe we're under the cellars," he said. "I'm no geologist, but this looks to me exactly the same sort of stone as that one that moved and we sealed up. We are in the Priory!"

"Right under the ground?" she asked. "Below the cellars even?"

"I'm not sure, but I think we must be. The place feels like a tomb, much more so than the cellars did." He looked round again. "Why, what fools we've been not to think of it! Didn't those old monks often have underground passages leading from the monastery to the chapel?"

"Yes, I believe they did," she said. "You think that's where we are? But this is a room!"

"Cut, if I'm not much mistaken, in the foundations of the house. I don't know much about monasteries, but I suppose the monks must have had a use for an underground room or so. Storing valuables in times of stress, and all that sort of thing."

"But the light!" she objected. "There's no electricity at the Priory."

"It must be worked by a plant. Good God!"

"What?" she said quickly.

"At the Bell! That big plant I saw there! But it can't possibly…' He broke off, utterly bewildered.

"Did you see a plant there? You never told me."

"I forgot about it. It was one day when Charles and I were there. I got into the engine-room, and I was just thinking what a ridiculously big machine it was for the work it had to do when Spindle hustled me out. Yes, by Jove, and I wondered at the time why he seemed so upset at finding me there. But Wilkes gave a plausible sort of explanation, and I never thought any more about it. Why, good Lord, do you realise that if I'm right, and it's that plant that produces this light, and works the machine we can hear, Wilkes must be in this, up to the eyes?"

"Wilkes?" she repeated incredulously. "That fat, smiling landlord? He couldn't be!"

"I don't know so much. And that throws a fresh light on it. Strange! He's staying at the Bell. For all we know he and Wilkes are hand in glove over this."

"Oh, no!" she said. "It isn't Michael Strange! It can't be! Not after what he said to me! No, no, I won't believe that!"

He did not press the point. He stood still, listening to the throb and the muffled roar of the machine, trying to think what it could be. The noise it made stirred some chord of memory in his brain. Margaret started to speak, and he signed to her to be quiet, with a quick frown and a finger held up.

Suddenly he remembered. Once, a couple of years before, he had been shown over a model printing works. He swung round, and exclaimed beneath his breath: "Margaret! I believe it's a printing press!"

She waited, searching his face. He seemed to be listening more intently than ever. "I don't see…' she began.

"Forgers!" he said. "I can't see what else it can possibly be - if it is a press."

"Forgers?"

"Probably forgers of bank-notes. I don't know." He came back to the table and sat down on the edge of it. "Let's get this straight. I believe we've hit on the secret of the Priory. If there's a gang of forgers at work here that would account for the efforts to get us out of the house. Jove, yes, and what a god-sent place for a press! Empty house, reputation for being haunted, only needed a little ghost-business to scare the countryside stiff, and to scare the former tenants out! I can't think why we never even suspected it."

"But Peter, it's fantastic! How could a gang of forgers know of this underground passage, and that sliding panel?"

"Not the gang, but the man at the head of it. The man who stole the book from the library, and tore the missing pages from the copy at the British Museum. The Monk, in fact."

"You mean Michael Strange, don't you?"

"I don't know whether I mean him or not, but it's clear that the Monk's no ordinary forger. He's someone who knew something about the Priory, someone who's devilish thorough and devilish clever."

She caught his hand, pressing it warningly. The bolts were being drawn back from the door of their cell. Peter thrust her behind him, and turned to face the door.

It opened, and the first thing they saw was the blunt nose of an automatic. A rough voice said: "Keep back, both of you."

They obeyed; there was nothing else to do. The door opened farther, and they saw a man standing there in the rough clothes of a country labourer. A handkerchief was tied round the lower half of his face, and a cloth cap was on his head. He had a bottle of water in his left hand, and this he set down on the floor. "Keep as you are!" he warned them, and took a step backwards, feeling behind him. He pulled a second chair in, and thrust it into the cell. "You can have that, and the water," he said. "And I wouldn't waste my breath shouting for help, if I was you. No one'll hear you, not if you shout till you're black in the face."

"Where are we?" Peter said, not that he had much hope of getting an answer.

"You're where no one'll ever think to look for you," the man replied.

Margaret said: "But you can't keep us here! Oh please, don't go! You couldn't leave us here to starve!"

"It's none of my business," was the callous answer. "And there's precious little the Monk stops at, I can tell you. You've interfered with him. That's what happens to people as cross the Monk's path." He drew his thumb across his throat in a crude descriptive gesture.

"Look here," Peter said, "I'm a pretty rich man, and if you get us out of this there's a fat reward waiting for you, and no awkward questions asked."

The man laughed. "Me? No bloody fear! Know what happened to Dooval? I've got no wish to go the same road, thank you kindly."

"I'll see nothing happens to you."

"Oh, you will, will you? Think you could stop the Monk? Well, there ain't a soul that knows him, and if you had a guard of fifty policemen he'd still get you. You wouldn't clear out of the Priory, you kept on nosing round after the Monk. And he's got you, and you talk about escaping! You won't do that, my fine gentleman, don't you fret. Nor no one won't recognise you if ever they finds you, for you'll be no more'n a skeleton. You crossed the Monk's path." With that he gave another of Isis brutal laughs, and went out, and shot the bolts home again.

Margaret sat down limply. "Peter, he can't mean that! No one could be as awful as that!"

"Of course they couldn't, Sis. Keep a stiff upper lip. liven supposing they do mean to clear out and leave us to rot, do you suppose Charles is going to do nothing?"

"But he said - no one would ever think to look for us here. Oh, Peter, why ever didn't we leave the Priory as Celia wanted?"

"Nonsense!" he said bracingly. "When Charles finds we've disappeared he'll pull the Priory down stone by stone. Listen, Sis! Don't give way! Already Charles knows there's something odd about the place. You don't suppose he and Celia would calmly give us up for lost when they must guess we're somewhere in the house? They'll have Scotland Yard on to it, and the whole countryside will be up. There isn't the slightest doubt that they'll find us."

She pointed out the water-bottle. "And we've got that — to last us till they do find us. It might take them weeks. Or perhaps the Monk will do as that man meant, and kill us."

"If he were going to kill us he'd hardly have bothered to let us have any water, or a second chair," Peter pointed out. "Sis, if you let go of yourself, you're not the girl I take you for. We may even find a way out ourselves. My dear kid, people don't get buried alive in the twentieth century!"

She knew that he was talking more to reassure her than from any real conviction, but she pulled herself together. "Yes. Of course. Sorry. Do you suppose this machine goes on all day, or will they all go away?"

"Go away, I should think. Too risky to work by day. When they've cleared off we can try and force that shutter back. I might be able to reach the top bolt, and that would give us a better chance of breaking the door down. Or I might be able to drive the wood in with the help of one of the chairs. What we've got to do is to keep our spirits up and talk of something else till the gang has gone. Wonder how they ventilate this place?"

She tried to follow his lead. "Yes, they must have some sort of ventilation, mustn't they? And though it's musty, and sort of close, it isn't airless, is it? How would they do it?"

"Don't quite know. If they've got power enough to work a machine they've probably rigged up some system of fans, same as they have in mines. But there must be an outlet somewhere, and that's what I can't make out."

They speculated on this for some time in rather a halfhearted fashion. Then Peter produced his cigarette-case, and they lit up, and smoked for a while, trying to think of something cheerful to talk about.

It was not only damp, but also cold, in the stone room, and Margaret had no coat. Peter saw her shiver, and began to take off his coat. "Sis, why didn't you sing out? You must be frozen in that thin dress. Here, put this on."

She demurred, but he insisted, and at last she put it on gratefully: Peter looked at his watch. "Nearly one o'clock. I'd give something to know what old Chas is doing."

"Celia will be dreadfully worried," Margaret said. "I wonder what they thought when they found us gone? Oh, Peter, suppose they were late, and just jumped to the conclusion we'd gone to bed, and didn't bother to look?"

"You're forgetting Bowers," he reminded her. "He went to get the coal, and when he got back to the library and found no trace of us, he must have thought it a trifle odd. I'll tell you what, Sis, that fire of yours was a stroke of genius. Because when the others hear how we took the trouble to light it they're bound to smell a rat. They can't think we went to bed, or strolled out for a walk, or anything like that."

These cheerful surmises occupied them for another half-hour, each one producing fresh reasons why Charles and Celia must guess what had happened. But they could not keep it up for ever, and again silence fell between them, and they sat busy with their much less cheerful thoughts.

Peter was chiefly anxious on the score of time. Though he spoke optimistically to Margaret he was less certain in his own mind that the Monk would not leave them to starve. He could not but remember Duval's fate, and the cold-blooded way in which that murder had been carried out. He did not doubt that before he gave up hope of finding the missing pair Charles really would demolish the Priory, but it might be too late by then. They could hardly hope that Charles too would hit on the panel in the library, for thinking it over, Peter realised that no one could guess that they had been kidnapped there. It would be much more likely that Charles would think they had gone out into the grounds. One thing Peter felt sure about: Charles would connect Michael Strange with this. Therein lay the greatest hope of a swift deliverance, for Strange might be made to talk.

Margaret's thoughts were by no means so reasoned or consecutive; she was still shaken by the terrifying experience she had gone through, and it seemed as though her brain could do nothing but repeat scraps of what Strange had said to her that day at the Inn. He had said it was no use supposing that she would ever look at a man in his "line of business." But he had said that from him she stood in no danger. Yes, but had he not added that he was not the only person mixed up in this? He had said too that there was danger, and that he might be powerless to help her. Unless he was the most accomplished and heartless liar he could not, on the face of it, be the Monk. It was possible that he was working under the Monk's orders, and if that were so Margaret felt convinced that the Monk had some unbreakable hold over him. He had told her that he must go on with the job he had undertaken. What else could that mean?

Peter's voice broke into her thoughts. "Margaret, you say the Monk lugged me in here. What did he look like?"

She gave a shiver. "You've seen pictures of those Inquisition people? Well, like that. He's got a long black robe on, with a cord round the waist, and a cowled hood drawn right down over his head and face. And do you remember what Aunt Lilian said about the black hand that pointed at her? Well, that was true. He wears black gloves, sort of cotton ones, with buttons, only he doesn't do them up. That was the only bit of him you could see for the disguise - his wrists. I particularly noticed, because it was the only thing about him that looked human. There was a button off one glove, too. Isn't it funny what stupid little things one fixes on?"

"A button off," Peter said. "Well, I thought as much."

"Why? What did you think?"

"Nothing. Something the police told us, and we weren't to repeat. Could you see what sort of build he was?"

"No, not very well with that loose robe on. Fairly tall, but not out of the way. A powerful man, because he managed to drag you to this place, and I couldn't see anyone else helping him. And his arm felt like steel when he held me."

"And he didn't say anything?"

"No. That seemed to make him even more sinister. That, and the dreadful chuckle."

"Doesn't really help us much," Peter said. He looked at his watch again. "Half past two. Look here, Sis, I think you'd better try and get some sleep. You've had a very strenuous time, and you're looking fagged out. And you mustn't forget we shall have a busy time ahead of us when this crowd clears off. Suppose you were to sit on my knee. Think you could snooze a bit with your head on my shoulder?"

She shook her head. "I couldn't, Peter. And I'm not a light weight, you know. I should wear you out."

"Oh no, you wouldn't!"

"Really, I'd rather not. I'm not sleepy. Anything but. Let's play some guessing game to keep ourselves occupied. Animal, vegetable, or mineral. You start."

"All right," he said. There was a pause. "I've thought. Go ahead."

The game seemed dreary beyond relief, but they kept on at it valiantly for nearly an hour. Then Margaret gave it up, and they began to wonder again what Charles and Celia were doing.

It was nearly four o'clock when the noise of the engine suddenly ceased. Margaret instinctively felt for Peter's hand. They sat in silence, listening, and presently they heard a door open and a murmur of voices. They could distinguish no voice they knew, nor could they catch what was said. Footsteps sounded retreating in the distance, and when these had died away they heard a key grate in a lock. Someone had remained behind, and there could be little doubt who that someone was.

Peter gently pulled Margaret to her feet, and led her to the wall alongside the door, so that she should be out of range of a shot fired through the grille. He placed himself as near to the door as he dared, determined to make a fight for it if the Monk came into the room.

But no one came. They heard the padding footstep which Margaret had described, and it died away as the others had done.

After the noise of the machine the silence that now hung over the tomb-like placee was so profound that Margaret felt that she knew at last what was meant by "hearing a silence." Nothing broke it, and she realised with a feeling of panic how completely buried alive they were. She felt she dared not speak, but presently Peter turned and said; "Gone. We'd better wait a bit before we get to work."

She nodded. The palms of her hands felt cold and sticky. She had an awful fear that the Monk might be still there, listening to them, waiting.

The minutes crept by. Peter whispered: "I'm going to give him half an hour's grace, just in case he hasn't gone. We've got loads of time. Let's sit down again. But if I say "move" get back to this wall again. See?"

"Yes," she replied. "We'd - we'd better go on talking, hadn't we?"

"That's the idea. Let's play I love my love with an A, as we used to when we were kids."

This programme was faithfully carried out, and since neither of them seemed to be able to think of drinks beginning with D, or attributes beginning with Q it took them more than half an hour to struggle through the alphabet. When they had at last come to the end, Peter got up. "I think it's safe enough now," he said. "If he were coming to do us in he wouldn't wait all this time. You sit still. I'm going to try and move that shutter."

For perhaps twenty minutes he tried by every means lie could think of to force it open, but it was of no avail. He banged on the door, to test the thickness of the wood. It sounded very solid, but he could at least try to break through. He picked up one of the chairs, and drove it with all his might against the door until one of its legs broke, and he was forced to pause for a while to get his breath. He sat down on the table, wiping the sweat from his face. "Well - I'm warm enough now, anyway," he said, trying to coax a smile into Margaret's wan countenance.

She did smile, but it was a pathetic effort. He patted her hand. "Cheer up, Sis: we'll get out all right."

He sat still for a few minutes, trying to think what other implements he could use against the door. He felt Margaret's hand gripping his arm, and glanced down at her. Her eyes were fixed on the door, and she was white as death. He looked quickly in the same direction, and saw what had attracted her attention. Inch by inch the shutter was sliding back.

"Move!" Peter said under his breath, but it seemed as though she either did not hear him, or dared not stir. He slipped in front of her, shielding her; there was no time to force her over to the wall.

The panel slid still farther; they saw a cowled face behind the grille, and through the slits in the cowl eyes glittered as the light caught them.

Peter stood perfectly still, and his mouth felt unpleasantly dry all at once.

The sinister face disappeared; there was a sound of bolts being drawn, and the door was opened. On the threshold stood the Monk, an automatic in his right hand. He put up his other hand, and pulled the cowl back from his head.

A bitter cry broke from Margaret. "My God! You!" she gasped.

For the Monk was none other than Michael Strange.