"Where did you meet?" I asked, interested.

Next morning, we found the Dulcibella wrapped in thick fog, which meant, of course, that nothing could be done until it lifted. After breakfast, we heard someone on deck, and a short, grey-haired man appeared in the cabin doorway.

"In an ugly place, in ugly weather," he replied, very seriously. "Has he not told you?"

"Bartels!" cried Davies. "Was that the Johannes that I heard arrive last night? Have some coffee." He spoke in his very poor German. "This is my friend, Carruthers. Captain Bartels of the Johannes," he added to me, and went to make some coffee.

Bartels said quietly to me, "It is good for Captain Davies to have a friend with him. He is a fine young man, but he is too brave, he takes too many risks."

Here it was again, the suggestion of some mystery, some dangerous event that I did not know about. I decided there and then to ask Davies to tell me the truth.

Just then he came back. "Bartels helped me out of a bit of trouble in the North Sea, didn't you, Bartels?"

"You're not very good at hiding things," I replied. "Go on."

"It began near Norderney," I said. "About the 9th of September."

"How did you guess that?" he asked in surprise.

He drank his coffee, and before he went, he advised Davies in a fatherly way to think again about going home before the winter began. Davies went with him back to his own boat, but returned at once, and sat down opposite me in the cabin. I think he knew what was coming.

"It was nothing," said Bartels. "But I've told you before, Captain, the North Sea is no place for your little boat at this time of the year."

"Well, you're right. Norderney. I'd been asking the local people about ducks, and they told me I should ask a German called Dollmann, with a big yacht, who did a lot of shooting. On the 9th of September I came across his yacht, the Medusa. She was very big, very smart too -- new paint, and a crew in uniform. I decided to go and speak to him."

"What did he mean?" I asked.

"I'll tell you," said Davies. "I'll tell you the whole thing. It's a kind of confession, I suppose. It's been worrying me a lot, and perhaps you'll be able to help me. But it's for you to decide." He paused for a second. "Something happened when I was in the Frisian Islands that I haven't told you about."

"Just a minute," I said. "Let's have a look at the chart."

"What was he like?" I asked.

"Here's Norderney," he said, spreading out the chart. "There's a harbour at the west end of the island, the only real harbour on the islands. The Medusa was anchored near it and I rowed over after dinner, and was taken to the main cabin. It was very grand. Dollmann was finishing dinner."

"About fifty, tall and thin, with grey hair and a short grey beard," replied Davies. "I asked about the duck shooting, and he said that there was none at all. But he wanted to know all about me and what I was doing there. We talked for a long time and he was quite friendly when I left. I intended to sail on eastwards next day, but Dollmann came to visit me on the Dulcibella, and then invited me to dinner on the Medusa a couple of times. In the end I stayed three more days anchored at Norderney."

"Well, we talked, and -- er -- I met his daughter two or three times. I hadn't seen her that first evening."

"How did you spend your time?" I asked.

"What was she like?" I asked.

"Oh! A very nice girl," he replied, turning a little pink. "Finally, we left Norderney together. Dollmann said the Baltic would be better for duck shooting. We agreed to sail together as far as Cuxhaven. He was sailing to Hamburg and I was going to take the new ship canal to Kiel. It's about a hundred kilometres from Norderney to Cuxhaven."

Davies paused, looking at the chart. "We left on the morning of 13th September," he began again. "The weather was bad, and there was a strong wind from the north-west. It was nothing for a big yacht like his, of course, but I soon realized I had been a fool to set out. After Wangeroog, the last of the islands, the wind got really strong, but it was too late to turn back by then. The sand stretches twenty-five kilometres from Cuxhaven right out to the Scharhörn, so you have to go round the Scharhörn to reach Cuxhaven, and I knew the sea would be extremely rough there. Suddenly I saw the Medusa was waiting for me to get closer. As I reached her, Dollmann shouted to me, slowly and clearly, 'It's too rough for you to go round the Scharhörn. Follow me. I'll show you a short cut through the sandbanks.'"

Davies paused, to point out the places on the chart. "Look, here's the Telte, it's a wide channel through the sands. It's all right if you know your way, but later on it's cut in two by the Hohenhörn sandbank, and it gets very shallow and difficult. Dollmann seemed to know what he was doing, so, after a moment's thought, I held up my arm to show that I would follow him. You asked me if I ever took a pilot. That was the only time."

"Suddenly I saw the waves breaking on the Hohenhörn right in front of me. I tried to steer along the edge of the sandbank, hoping to find a way through. But the wind carried the Dulcibella violently on to the sandbank. The next wave carried me further on to the bank and into a little channel. I can't describe the next few minutes. My hand had been hurt, and the helm damaged, in that first bump, and I had no control over the boat. The waves were crashing all around me, and finally I ran aground."

Davies spoke bitterly. "I followed him into the Telte channel, but then I saw he wasn't waiting for me. The Medusa was sailing much faster than I could, and soon disappeared into the mist and rain. There was nothing I could do. I couldn't turn round and go back. At high tide, as it was then, all the sand is covered, so you can't see the sandbanks or the channels, and there are no buoys. The wind was behind me too, and was very strong by this time. It was driving me straight on to the Hohenhörn sandbank."

"A spy?" I said. "What do you mean? A spy of what -- of whom?"

He said it very simply, and I stared at him in astonishment.

Davies shook his head. "I was so angry with myself, you can't imagine. I couldn't do anything because my hand was useless. But that's when Bartels saw me and came to help. He'd taken shelter in a deeper part of the channel that I was in. He saw I was in difficulties, so he and his boy rowed across to me. They soon had the sails down, and pulled me away from the sand and down the channel, to where the Johannes lay. He's a good man, Bartels. If it weren't for him, I wouldn't be here now."

"The next day he helped me repair the damage to the helm. He was sailing for the Eider River and on to the Baltic that way. It's longer than going by the new ship canal but both routes come out at Kiel. I went with him, and three days later I was in the Baltic. I wrote to you a week after I got there. You see, by then I had realized that Dollmann was a spy."

"Well, I'm not sure that 'spy' is the right word, but he's something very bad. He deliberately tried to make me go aground, you see. He tried to kill me."

"Are you sure?" It was difficult to believe it.

"Oh yes!" said Davies calmly. "I've worked it all out. Dollmann knew his way through the sands, by the Telte channel, and his yacht was big enough to manage it. You see, the Telte divides into two before the Hohenhörn sandbank. Dollmann turned north and then into the channel that goes around the Hohenhörn. But before he turned, he led me straight for the sandbank. And he deliberately left me behind, so I didn't know that he had turned. He meant me to keep going straight ahead. I should have been broken to pieces on the Hohenhörn."

"Why weren't you?" I asked.

Davies pointed again at the chart. "Look," he said. "The Telte divides into two quite big channels, which go round the Hohenhörn to the north and the south. But there's also a very narrow channel that goes through the middle. It's so small that I hadn't noticed it, when I looked at the chart before we sailed. That's the one I was carried into. If I had been on the sandbank, the Dulcibella would have broken up in three minutes. I was just lucky that day."

"After that he did his best to get rid of me. He said there were no ducks, that the Baltic was very good for sailing and for ducks, and he offered to show me the way. He wanted to get me away from those islands. I don't think he meant to kill me at first, but when the chance came later on, he just took it."

Davies shook his head. "Look at it from the beginning," he said. "The first time I met Dollmann, he asked me all sorts of questions about what I was doing and why. I was terribly enthusiastic about my voyage and talked quite freely. I told him that I was exploring the channels between the islands, working out all the movements of the sandbanks, and making notes about it all, because the English charts were so hopelessly out of date."

Lucky -- and brave, I thought to myself. "But what makes you think he's a spy?" I asked. "Perhaps he was in difficulties too, and lost sight of you by accident?"

"But what about his crew?" I asked. "Surely they would have noticed."

"There wasn't anyone else on deck, when he told me about the short cut. He was steering the Medusa himself."

"And his daughter? Do you think she wanted to get rid of you, too?"

Davies's face suddenly went very red. "I'm sure she knew nothing about it," he said fiercely. He began trying to light his pipe again, and I thought I could guess another reason why he had agreed to sail with Dollmann.

"But that's just the point," cried Davies. "He's not German. He's an Englishman."

"Let's look at it from Dollmann's point of view," I said. "A German finds an Englishman exploring the German coast, and checking the charts. Perhaps he thought you were the spy."

"Yes, I'm sure of it," said Davies. "Every time I spoke to him on the Medusa he spoke German. He said he only knew a few words of English. And when he offered to show me the short cut through the sands, he shouted in German. Now, you know that I never like taking a pilot, so I hesitated before agreeing. He must have thought I hadn't understood him, so he shouted again, only this time in English, without any German accent."

"An Englishman!"

"And if he was planning to lead you to your death on the Hohenhörn," I said, "it wouldn't matter if you guessed that he wasn't German!"

"That's right," agreed Davies eagerly. "I knew you'd understand. I'm sure he's an Englishman, working for the German government and giving them information. He's been living here for years, and has a house on Norderney. Oh! And I met a friend of his, a Commander von Brüning, in the German navy. He came on board the Medusa one day when I was there. He's captain of the gunboat Blitz, on guard duty for the fishing boats around the islands."

"Did von Brüning seem to know Dollmann well?"

He took down a map of Germany from the shelf and spread it on the table. "Look at Germany. It's the strongest nation in Europe, and it's led by the young Kaiser, who's a great man for getting things done. Their industry is growing very fast and, in order to have markets for what they produce, they need colonies. To get and keep these colonies, and to protect their shipping, they need a strong navy. They have only a small one at present, but it's very good, and they're building more ships as fast as they can. In Britain we already have a strong navy, because we live on an island, and we need to protect the sea routes between us and our colonies. Most of our food comes to us by sea. If we lose control of the sea, we're finished. But Germany is in the very centre of Europe, and can get all she needs from her neighbours. She has the biggest army in the world. She can already compete with our industry, and soon she may be able to compete with our navy. And unfortunately, we're not ready for her. All our naval bases are on the south coast, opposite our old enemy, France. We have no bases in the North Sea. We should realize that Germany is the danger now, and do something about it."

"Yes, very well," replied Davies. "Now," he continued, "let me explain what I think is happening."

"Yes, I know," I said. "But go on."

Davies pointed at the map again. "Now look at the coast of Germany. It's very short and it's cut in two by Denmark. Most of the German coast is on the Baltic, which is not much use to them as it's too far from the Atlantic. That's why the Kaiser has built the new ship canal from Kiel to the River Elbe, so that he can move his ships from the Baltic to the North Sea quickly. The North Sea coast is the important one but it's very short -- three hundred kilometres at the most. And not all of it can be used. Most of the coastline is hidden behind sandbanks, or a line of islands. There's just one wide opening, with the mouths of the three big rivers, the Elbe, the Weser, and the Jade, leading to Hamburg, Bremen, and Wilhelmshaven. The important bit of coast is the hundred and twelve kilometres from Borkum to the Elbe, and that's the part that Dollmann stopped me exploring."

Davies paused and looked at me anxiously. "These are not just my ideas, you know. Other people worry about this too."

He paused again, looking at the sandbanks shown on the map. "If England were at war with Germany," he added, slowly and seriously, "the whole of that coast would be important, sands and all. There are channels through those sands that can only be used by small ships like Bartels" Johannes. In wartime the main sea routes to Hamburg and the other ports would be carefully guarded. But if we knew where the channels through the sands were, small gunboats could use them to attack German ships in the mouths of the big rivers. And, of course, German gunboats could use them to attack our ships off the coast. Then they could disappear among the sands, where our ships would be too big to follow them. All our warships need deep water to sail in, and can't possibly use those channels."

"I see," I said. I began to understand what Davies was trying to tell me. "So German gunboats could travel through the sands from Hamburg to Holland, and our North Sea ships couldn't get near them."

"That's right," said Davies. "Or of course, our gunboats could do the trip the other way, if we knew where the channels were. The trouble is, we don't know. None of our fishing boats use these waters and our charts are years out of date. It just happens that I enjoy sailing in waters like these and bringing the charts up to date."

"We can go back to the North Sea through the ship canal from Kiel," said Davies. "We could start for Kiel at once. The fog's lifting and there's a little south-west wind."

"Yes," agreed Davies. "But I'd like to know just what Dollmann is doing there."

"It must be something very important if he's prepared to kill you," I said. "And there's only one way to find out."

"I'm not surprised Dollmann wanted to get rid of you," I said.

Davies jumped up in excitement and hit his head on the cabin ceiling. "You mean you'll come?" he cried.

"Of course," I said. "We'll have to go back to Norderney to find out why an Englishman is watching those waters and keeping other people out of them. When do we start?"

"How far is it?" I asked. "It'll mean sailing all night!"

"It's only about forty kilometres," he replied. "I know it's not the best wind we could have, but we ought to take the chance."

It was hopeless arguing about winds with Davies, so we set off lunchless, but full of excitement.