Isabel Worth leaned back in the comfortable seat by Granet’s side and breathed a little sigh of content. She had enjoyed her luncheon party a deux, their stroll along the sands afterwards, and she was fully prepared to enjoy this short drive homewards.

“What a wonderful car yours is!” she murmured. “But do tell me—what on earth have you got in behind?”

“It’s just a little experimental invention of a friend of mine,” he explained. “Some day we are going to try it on one of these creeks. It’s a collapsible canvas boat.”

“Don’t try it anywhere near us,” she laughed. “Two of the fishermen from Wells sailed in a little too close to the shed yesterday and the soldiers fired a volley at them.”

Garnet made a grimace.

“Do you know I am becoming most frightfully curious about your father’s work?” he observed.

“Are you really?” she replied carelessly. “For my part, I wouldn’t even take the trouble to climb up the ladder into the workshop.”

“But you must know something about what is going on there?” Granet persisted.

“I really don’t,” she assured him. “It’s some wonderful invention, I believe, but I can’t help resenting anything that makes us live like hermits, suspect even the tradespeople, give up entertaining altogether, give up even seeing our friends. I hope you are not going to hurry away, Captain Granet. I haven’t had a soul to speak to down here for months.”

“I don’t think I shall go just yet,” he answered. “I want first to accomplish what I came here for.”

She turned her head very slowly and looked at him. There was quite a becoming flush upon her cheeks.

“What did you come for?” she asked softly.

He was silent for a moment. Already his foot was on the brake of the car; they were drawing near the plain, five-barred gates.

“Perhaps I am not quite sure about that myself,” he whispered.

They had come to a standstill. She descended reluctantly.

“I hate to send you away,” she sighed, “it seems so inhospitable. Will you come in for a little time? The worst that can happen, if we meet dad, is that he might be rather rude.”

“I’ll risk it with pleasure,” Granet replied.

“Can I see your collapsible boat?” she asked, peering in behind.

He shook his head.

“It isn’t my secret,” he said, “and besides, I don’t think my friend has the patent for it yet.”

The sentry stood by and allowed them to pass, although he looked searchingly at Granet. They walked slowly up the scrubby avenue to the house. Once Granet paused to look down at the long arm of the sea on his left.

“You have quite a river there,” he remarked.

She nodded.

“That used to be the principal waterway from Burnham village. Quite a large boat can get down now at high tide.”

They entered the house and Isabel gave a little gesture of dismay. She clutched for a moment at Granet’s arm. An elderly man, dressed in somber black clothes disgracefully dusty, collarless, with a mass of white hair blown all over his face, was walking up and down the hall with a great pair of horn-rimmed spectacles clutched in his hand. He stopped short at the sound of the opening door and hurried towards them. There was nothing about his appearance in the least terrifying. He seemed, in fact, bubbling over with excited good-humour.

“Isabel, my dear,” he exclaimed, “it is wonderful! I have succeeded! I have changed the principles of a lifetime, made the most brilliant optical experiment which any man of science has ever ventured to essay, with the result—well, you shall see. I have wired to the Admiralty, wired for more work-people. Captain Chalmers, is it not?” he went on. “You must tell your men to double and redouble their energies. This place is worth watching now. Come, I will show you something amazing.”

He turned and led them hastily towards the back door. Isabel gripped Granet’s arm.

“He thinks you are the officer in command of the platoon here,” she whispered. “Better let him go on thinking so.”

Granet nodded.

“Is he going to take us to the workshop?”

“I believe so,” she assented.

They had hard work to keep up with Sir Meyville as he led them hastily down the little stretch of shingle to where a man was sitting in a boat. They all jumped in. The man with the oars looked doubtfully for a moment at Granet, but pulled off at once when ordered to do so. They rowed round to the front of the queer little structure. A man from inside held out his hand and helped them up. Another young man, with books piled on the floor by his side, was making some calculations at a table. Almost the whole of the opening of the place was taken up by what seemed to be a queer medley of telescopes and lenses pointing different ways. Sir Meyville beamed upon them as he hastily turned a handle.

“Now,” he promised, “you shall see what no one has ever seen before. See, I point that arrow at that spot, about fifty yards out. Now look through this one, Isabel.”

The girl stooped forward, was silent for a moment, then she gave a little cry of wonder. She clutched Granet’s arm and made him take her place. He, too, called out softly. He saw the sandy bottom covered with shells, a rock with tentacles of seaweed floating from it, several huge crabs, a multitude of small fishes. Everything was clear and distinct. He looked away with a little gasp.

“Wonderful!” he exclaimed.

Sir Meyville’s smile was beatific.

“That is my share,” he said. “Down in the other workshop my partners are hard at it. They, too, have met with success. You must tell your men, Captain Chalmers, never to relax their vigil. This place must be watched by night and by day. My last invention was a great step forward, but this is absolute success. For the next few months this is the most precious spot in Europe.”

“It isn’t Captain Chalmers, father,” Isabel interrupted.

Sir Meyville seemed suddenly to become still. He looked fixedly at Granet.

“Who are you, then?” he demanded. “Who are you, sir?”

“I am Captain Granet of the Royal Fusiliers, back from the Front, wounded,” Granet replied. “I can assure you that I am a perfectly trustworthy person.”

“But I don’t understand,” Sir Meyville said sharply. “What are you doing here?”

“I came to call upon your daughter,” Granet explained. “I had the pleasure of meeting her at lunch at Lady Anselman’s the other day. We have been playing golf together at Brancaster.”

Sir Meyville began to mumble to himself as he pushed them into the boat.

“My fault,” he muttered,—“my fault. Captain Granet, I thought that my daughter knew my wishes. I am not at present in a position to receive guests or visitors of any description. You will pardon my apparent inhospitality. I shall ask you, sir, to kindly forget this visit and to keep away from here for the present.”

“I shall obey your wishes, of course, sir,” Granet promised. “I can assure you that I am quite a harmless person, though.”

“I do not doubt it, sir,” Sir Meyville replied, “but it is the harmless people of the world who do the most mischief. An idle word here or there and great secrets are given away. If you will allow me, I will show you a quicker way down the avenue, without going to the house.”

Granet shrugged his shoulders.

“Just as you will, sir,” he assented.

“You can go in, Isabel,” her father directed curtly. “I will see Captain Granet off.”

She obeyed and took leave of her guest with a little shrug of the shoulders. Sir Meyville took Granet’s arm and led him down the avenue.

“Captain Granet,” he said gravely, “I am an indiscreet person and I have an indiscreet daughter. Bearing in mind your profession, I may speak to you as man to man. Keep what you have seen absolutely secret. Put a seal upon your memory. Go back to Brancaster and don’t even look again in this direction. The soldiers round this place have orders not to stand on ceremony with any one, and by to-night I believe we are to have an escort of Marines here as well. What you have seen is for the good of the country.”

“I congratulate you heartily, sir,” Granet replied, shaking hands. “Of course I’ll keep away, if I must. I hope when this is all over, though, you will allow me to come and renew my acquaintance with your daughter.”

“When it is over, with pleasure,” Sir Meyville assented.

Granet stepped into his car and drove off. The inventor stood looking after him. Then he spoke to the sentry and made his way across the gardens towards the boat-shed.

“I ought to have known it from the first,” he muttered. “Reciprocal refraction was the one thing to think about.”

Granet, as he drove back to the Dormy House, was conscious of a curious change in the weather. The wind, which had been blowing more or less during the last few days, had suddenly dropped. There was a new heaviness in the atmosphere, little banks of transparent mist were drifting in from seawards. More than once he stopped the car and, standing up, looked steadily away seawards. The long stretch of marshland, on which the golf links were situated, was empty. A slight, drizzling rain was falling. He found, when he reached the Dormy House, that nearly all the men were assembled in one of the large sitting-rooms. A table of bridge had been made up. Mr. Collins was seated in an easy-chair close to the window, reading a review. Granet accepted a cup of tea and stood on the hearth-rug.

“How did the golf go this afternoon?” he inquired.

“I was dead off it,” Anselman replied gloomily.

“Our friend in the easy-chair there knocked spots off us.”

Mr. Collins looked up and grunted and looked out of the window again.

“Either of you fellows going to cut in at bridge?” young Anselman continued.

Granet shook his head and walked to the window.

“I can’t stick cards in the daytime.”

Mr. Collins shut up his review.

“I agree with you, sir,” he said. “I endeavoured to persuade one of these gentlemen to play another nine holes—unsuccessfully, I regret to state.”

Granet lit a cigarette.

“Well,” he remarked, “it’s too far to get down to the links again but I’ll play you a game of bowls, if you like.”

The other glanced out upon the lawn and rose to his feet.

“It is an excellent suggestion,” he declared. “If you will give me five minutes to fetch my mackintosh and galoshes, it would interest me to see whether I have profited by the lessons I took in Scotland.”

They met, a few moments later, in the garden. Mr. Collins threw the jack with great precision and they played an end during which his superiority was apparent. They strolled together across the lawn, well away now from the house. For the first time Granet dropped his careless tone.

“What do you make of this change in the weather?” he asked quickly.

“It’s just what they were waiting for,” the other replied. “What about this afternoon?”

“I am not scientist, worse luck,” Granet replied impatiently, “but I saw enough to convince me that they’ve got the right idea. Sir Meyville thought I was the man commanding the escort they’ve given him,—actually rowed me out to the workshop and showed me the whole thing. I tell you I saw it just as you described it,—saw the bottom of the sea, even the colour of the seaweed, the holes in the rocks.”

“And they’ve got the shells, too,” Collins muttered, “the shells that burst under water.”

Granet looked around. They were playing the other end now.

“Listen!” he said.

They paused in the middle of the lawn. Granet held up his handkerchief and turned his cheek seaward. There was still little more than a floating breath of air but his cheek was covered with moisture.

“I have everything ready,” he said. “Just before we go to bed to-night I shall swear that I hear an aeroplane. You’re sure your watch is right to the second, Collins?”

“I am as sure that it is right,” the other replied grimly, “as I am that to-night you and I my young friend, are going to play with our lives a little more carelessly than with this china ball. A good throw, that I think,” he went on, measuring it with his eye carefully. “Come, my friend, you’ll have to improve. My Scotch practice is beginning to tell.”

Geoffrey Anselman threw up the window and looked out.

“Pretty hot stuff, isn’t he Ronnie?” he asked.

Granet glanced at his opponent, with his bent shoulders, his hard face, hooked nose and thin gold spectacles.

“Yes,” he admitted quietly, “he’s too good for me.”