Bill gazed at him without saying anything.

"Rather good, isn't it?" said Antony, coming closer and pointing to the bed. "Come on; the sooner we get out now, the better."

He led the way out of the window, the silent Bill following him. They reached the ground safely and noiselessly, went quickly across the lawn and so, over the fence, into the park. It was not until they were out of sight of the house that Bill felt it safe to speak.

"I quite thought it was you in bed," he said.

"I hoped you would. I shall be rather disappointed now if Cayley doesn't call again. It's a pity to waste it."

"He came all right just now?"

"Oh, rather. What about you?"

Bill explained his feelings picturesquely.

"There wouldn't have been much point in his killing you," said Antony prosaically. "Besides being too risky."

"Oh!" said Bill. And then, "I had rather hoped that it was his love for me which restrained him."

Antony laughed.

"I doubt it.... You didn't turn up your light when you dressed?"

"Good Lord, no. Did you want me to?"

Antony laughed again and took him by the arm.

"You're a splendid conspirator, Bill. You and I could take on anything together."

The pond was waiting for them, more solemn in the moonlight. The trees which crowned the sloping bank on the far side of it were mysteriously silent. It seemed that they had the world very much to themselves.

Almost unconsciously Antony spoke in a whisper.

"There's your tree, there's mine. As long as you don't move, there's no chance of his seeing you. After he's gone, don't come out till I do. He won't be here for a quarter of an hour or so, so don't be impatient."

"Righto," whispered Bill.

Antony gave him a nod and a smile, and they walked off to their posts.

The minutes went by slowly. To Antony, lying hidden in the undergrowth at the foot of his tree, a new problem was presenting itself. Suppose Cayley had to make more than one journey that night? He might come back to find them in the boat; one of them, indeed, in the water. And if they decided to wait in hiding, on the chance of Cayley coming back again, what was the least time they could safely allow? Perhaps it would be better to go round to the front of the house and watch for his return there, the light in his bedroom, before conducting their experiments at the pond. But then they might miss his second visit in this way, if he made a second visit. It was difficult.

His eyes were fixed on the boat as he considered these things, and suddenly, as if materialized from nowhere, Cayley was standing by the boat. In his hand was a small brown bag.

Cayley put the bag in the bottom of the boat, stepped in, and using an oar as a punt-pole, pushed slowly off. Then, very silently, he rowed towards the middle of the pond.

He had stopped. The oars rested on the water. He picked up the bag from between his feet, leant over the nose of the boat, and rested it lightly on the water for a moment. Then he let go. It sank slowly. He waited there, watching; afraid, perhaps, that it might rise again. Antony began to count....

And now Cayley was back at his starting-place. He tied up the boat, looked carefully round to see that he had left no traces behind him, and then turned to the water again. For a long time, as it seemed to the watchers, he stood there, very big, very silent, in the moonlight. At last he seemed satisfied. Whatever his secret was, he had hidden it; and so with a gentle sigh, as unmistakable to Antony as if he had heard it, Cayley turned away and vanished again as quietly as he had come.

Antony gave him three minutes, and stepped out from the trees. He waited there for Bill to join him.

"Six," whispered Bill.

Antony nodded.

"I'm going round to the front of the house. You get back to your tree and watch, in case Cayley comes again. Your bedroom is the left-hand end one, and Cayley's the end but one? Is that right?"

Bill nodded.

"Right. Wait in hiding till I come back. I don't know how long I shall be, but don't be impatient. It will seem longer than it is." He patted Bill on the shoulder, and with a smile and a nod of the head he left him there.

What was in the bag? What could Cayley want to hide other than a key or a revolver? Keys and revolvers sink of themselves; no need to put them in a bag first. What was in the bag? Something which wouldn't sink of itself; something which needed to be helped with stones before it would hide itself safely in the mud.

Well, they would find that out. There was no object in worrying about it now. Bill had a dirty night's work in front of him. But where was the body which Antony had expected so confidently or, if there were no body, where was Mark?

More immediately, however, where was Cayley? As quickly as he could Antony had got to the front of the house and was now lying in the shrubbery which bordered the lawn, waiting for the light to go up in Cayley's window. If it went up in Bill's window, then they were discovered. It would mean that Cayley had glanced into Bill's room, had been suspicious of the dummy figure in the bed, and had turned up the light to make sure. After that, it was war between them. But if it went up in Cayley's room-

There was a light. Antony felt a sudden thrill of excitement. It was in Bill's room. War!

The light stayed there, shining vividly, for a wind had come up, blowing the moon behind a cloud, and casting a shadow over the rest of the house. Bill had left his curtains undrawn. It was careless of him; the first stupid thing he had done, but-

The moon slipped out again.... and Antony laughed to himself in the bushes. There was another window beyond Cayley's, and there was no light in it. The declaration of war was postponed.

Antony lay there, watching Cayley into bed. After all it was only polite to return Cayley's own solicitude earlier in the night. Politeness demanded that one should not disport oneself on the pond until one's friends were comfortably tucked up.

Meanwhile Bill was getting tired of waiting. His chief fear was that he might spoil everything by forgetting the number "six." It was the sixth post. Six. He broke off a twig and divided it into six pieces. These he arranged on the ground in front of him. Six. He looked at the pond, counted up to the sixth post, and murmured "six" to himself again. Then he looked down at his twigs. One-two-three-four-five-six-seven. Seven! Was it seven? Or was that seventh bit of a twig an accidental bit which had been on the ground anyhow? Surely it was six! Had he said "six" to Antony? If so, Antony would remember, and it was all right. Six. He threw away the seventh twig and collected the other six together. Perhaps they would be safer in his pocket. Six. The height of a tall man-well, his own height. Six feet. Yes, that was the way to remember it. Feeling a little safer on the point, he began to wonder about the bag, and what Antony would say to it, and the possible depth of the water and of the mud at the bottom; and was still so wondering, and saying, "Good Lord, what a life!" to himself, when Antony reappeared.

Bill got up and came down the slope to meet him.

"Six," he said firmly. "Sixth post from the end."

"Good," smiled Antony. "Mine was the eighteenth-a little way past it."

"What did you go off for?"

"To see Cayley into bed."

"Is it all right?"

"Yes. Better hang your coat over the sixth post, and then we shall see it more easily. I'll put mine on the eighteenth. Are you going to undress here or in the boat?"

"Some here, and some in the boat. You're quite sure that you wouldn't like to do the diving yourself?"

"Quite, thanks."

They had walked round to the other side of the pond. Coming to the sixth post of the fence, Bill took off his coat and put it in position, and then finished his undressing, while Antony went off to mark the eighteenth post. When they were ready, they got into the boat, Antony taking the oars.

"Now, Bill, tell me as soon as I'm in a line with your two marks."