Davies had another piece of news. "The Kormoran is here in harbour too. It must have been them watching us, surely? And then passing the information on to von Brüning."

"Almost certainly von Brüning wants to know more about us," I said. "We must be very careful what we say to him. Perhaps he'll come on board and ask to see our log."

I slept very comfortably that night, and was woken by the sound of Davies talking in his limited German to someone on the shore. When he came on board, he told me that he had met Commander von Brüning, who had invited us to have a drink in the village pub with him at twelve o'clock.

"In that case we must show it to him. Let's be open about it! I hate hiding things, anyway."

And so we decided on an important change of plan, to bring our log and charts out of their hiding-place, and be as honest as we could. But just how much did von Brüning know? Did he know that we had not fired a shot at a single duck in the North Sea, and that we had explored the sands all along the coast? Did he know about Dollmann's attempt to get rid of Davies, and Davies's lucky escape? We could not tell. So it would be safer to tell the truth as far as possible in the coming interview.

But first we tried to find out something about the Kormoran, so after breakfast we went for a walk round the village. The people were very friendly, and we stopped to talk to two of the fishermen. We asked them about the boats in the harbour, and they told us that the Kormoran was not a local fishing boat.

"She's from Memmert," they said. "She's trying to raise an old French ship, loaded with gold, that sank off Juist. Her captain, Herr Grimm, is in charge of the work. That's him over there." They pointed to a man standing on the bridge across the little stream that ran into the harbour.

We walked out on the sand to inspect this channel, and then walked slowly back. "Don't forget," I said, "when we talk to von Brüning, just be yourself. You need only tell one lie, about the trick Dollmann played you."

"All right, I'll leave you to do most of the talking. Look, there's Grimm again. Look at his boots as we pass him." When we did, we saw that Grimm was wearing shoes, though of course that did not prove he had left one of his boots on the Dulcibella.

"He's still away," replied von Brüning, "but his yacht is back at Norderney. His daughter must be there too."

It was a few minutes after twelve when we entered the village pub. Davies introduced me to Commander von Brüning, and we sat down and ordered something to drink. I must say, I liked von Brüning as soon as I saw him. He was tall, with fair hair and a short beard. His eyes were blue and friendly, but extremely intelligent. I was glad we had decided to tell the truth -- the commander was not a man you could trick easily. We had decided that Davies should ask immediately about Dollmann, his supposed friend. I was horrified to see Davies's face go pink as he asked his question in German, but then I remembered an obvious reason for his embarrassment. I had to make sure, however, that von Brüning also understood the reason for the embarrassment.

"She's a very fine boat," said Davies, his face getting even redder. Von Brüning smiled, looking thoughtfully at Davies. I saw a chance, and took it pitilessly.

"Oh good, we can call on Fräulein Dollmann," I said to Davies, smiling meaningfully at von Brüning at the same time. Davies looked even more miserable.

"Only part of the way," replied Davies. "The Medusa was too fast for me."

"Oh, yes! I remember," said von Brüning. "The weather was very bad that day. I thought you would have trouble round the Scharhörn."

"But you have seen Herr Dollmann since I have, surely?" said von Brüning. "Didn't you sail to the Elbe with him?"

"We didn't go round the Scharhörn," said Davies. "Dollmann showed me a short cut through the sands, but I lost him and ran aground."

"Where was this?" asked von Brüning.

"You mean Dollmann took you through the Telte channel in that sort of weather and you ran aground on the Hohenhörn? Is that where you lost him?"

"On the Hohenhörn," said Davies simply.

"No, he had already disappeared in the rain," replied Davies. "He couldn't have seen what happened. Anyway, it didn't matter. The tide was rising and I soon floated off. But I decided to spend the night in the shelter of the sandbank."

The commander's smile disappeared and his eyes opened wide. His surprise was so obvious that I was sure he had heard nothing of this before.

"I didn't go that way," Davies replied. "The wind was against it, so I sailed to the Eider River and on to the Baltic that way."

"Didn't they wait for you at the ship canal?" asked von Brüning.

"That's nothing to him," I said. "He prefers it. He anchored us the other day behind the Hohenhörn in a horrible wind; said it was safer than a harbour and much cleaner."

Commander von Brüning laughed suddenly and turned to me. "Really," he said, "your friend amuses me. He has the most terrifying adventures, and makes them sound perfectly ordinary."

"I'm surprised he didn't decide this storm was just the wind he needed to sail to England," said von Brüning.

"And no pretty daughter," laughed the commander.

"There was no pilot to follow, you see," I said, with a smile.

Davies frowned and looked so angry with me that I decided to say no more about Dollmann's daughter. I suddenly thought that if Grimm was working with von Brüning, the commander would know about the Dulcibella's night-time visitor. It would seem strange if we said nothing about it.

So I said, "By the way, I thought the local people were honest, but we had a thief on the yacht the other night."

"Talking about wrecks," I said, "isn't there one round here that's supposed to be full of French gold? Is that true?"

"Quite true," said von Brüning. "The Corinne. She sank in 1811 off the island of Juist with gold on board to pay Napoleon's army -- in English money it would be worth about one and a half million pounds."

"Has anyone found it?" I asked.

"Really?" he replied. "They're excellent people, but in the old days they used to take things from wrecks on this coast, so it's a way of life for them. They probably thought the Dulcibella was deserted."

"They found the wreck years ago, but it had broken up and the gold, being heavy, had sunk to the bottom. Several people have tried to find it but, of course, these sands keep moving all the time, so it's very difficult. Now a local company is trying. They're working from Memmert, an island near here. Herr Dollmann is one of the directors of the company. There's an engineer from Bremen involved, too -- he comes from time to time."

"Not yet, but I hope they will. I've put a little money into the company myself."

"And have they had any luck?" I asked.

The conversation continued, and he went on to find out from us, in the most natural yet skilful way, every detail of our explorations so far. As we talked, I was glad we had decided on telling the truth as far as possible, and gladder still that Davies was the man he was, eager, sincere, and completely believable.

"Oh, dear!" I said. "I hope I haven't been asking too many questions."

"You speak very good German, Herr Carruthers," said von Brüning at one point in the conversation.

"For your profession?" he asked.

"Not at all," von Brüning laughed. "It's no secret. Everyone on these islands knows all about it."

"I've spent some time studying in Germany," I replied.

"Yes," I replied. "I work in the Foreign Office." I would have preferred not to have given him that information, but there was probably a letter from my boss, with a Foreign Office stamp, waiting for me at Norderney post office. My name was known, and we were watched. So the letter might be opened.

"I'll be at Norderney myself very soon. Come and visit me there, will you? I'd like to show you the Blitz."

"Thanks very much," Davies and I said together, as warmly as we could manage.

"You'll never find them," said von Brüning, "without a local man to guide you. I can easily find you a good man --"

"Next week, but I'm hoping my boss will agree to give me a little more time," I said. "I've asked him to write to me at Norderney."

"I like this coast," said Davies. "And -- we want to shoot some ducks."

"It's very kind of you, commander," I said, "but we'd better get to Norderney first, to collect my post and see if I can stay longer or not."

"When do you have to be back at work?" he asked.

As we were leaving, von Brüning took me on one side.

"Oh! He's a free man," I said. "He'll sail around these islands until Christmas, I expect. So we're in no hurry."

"I see. And Herr Davies?"

"One word in private with you, Herr Carruthers," he said quietly. "It's about the Dollmanns. You know how your friend feels. I wouldn't encourage him, if I were you. Herr Dollmann came here three years ago, but we know very little about him or his background."

"I thought the Dollmanns were friends of yours," I said.

"Thanks. I'll remember," I said.

South of the island of Juist, and running right up to the mouth of the River Ems, there is a large sandbank. Its western edge remains uncovered at high tide, forming a small island, about three kilometres long, and from two hundred to five hundred metres wide. This island is Memmert. The chart showed only one building, which I guessed was the centre for Dollmann's company. The island stands on the deep water channel of the Ems, providing a shelter for ships to anchor, even at low tide.

"I know them, but I know everybody. I speak only as someone who wishes your friend well, you understand. I think you should forget about calling on the family in Norderney. That's all, just a warning."

He gave me a long, serious look, and I could see that he was not going to say any more.

The questions in my mind were, "How much do you know, and what do you mean?" But I could not ask them.

"Where exactly is Memmert?" I asked. Davies unrolled the chart and pointed at it. Then he threw himself on one of the seats, where he lay for some time, deep in thought.

Davies and I walked back to the yacht in silence, and went down to the cabin.

The story of the French wreck and its gold provided a very good reason for Dollmann, Grimm, and von Brüning to be seen together, and to spend time on Memmert, especially as von Brüning had put money into the company. I was curious about Memmert. The more I thought about it, the more I believed that it might help us to solve the riddle.

I thought hard about our conversation with von Brüning. Was he giving friendly advice to two young men on holiday, or a serious warning to two foreign spies? Perhaps he could not decide which we were. I was sure von Brüning had not known about Dollmann's attempt to kill Davies. He had guessed it, of course, when Davies told him about the short cut through the Telte channel.

Davies had still not spoken. He was annoyed with me, and I knew why. But I was annoyed with him too. There was an important piece of the puzzle that he had not told me about. I was waiting for him to speak first but, in the end, his silence was too much for me, and I had to break it.

"Look, Davies," I said, "I'm sorry I mentioned you and Fräulein Dollmann." No answer. I tried again, "I couldn't help it, you know."

"You're being very unreasonable," I replied. "We agreed the best thing to do was to tell the truth. Didn't you see that he was trying to trap us?"

"You haven't been fair with me, have you?" I asked. "There's something about her you haven't told me."

"No, but we could go to Memmert," I said.

"Well, we've got to go to Norderney…" I began, but Davies interrupted me.

"Well, you see, I had to talk about her, for two reasons. First, you seemed very embarrassed when we were talking about the Dollmanns. And second, although you described Dollmann's short cut very well, in the way we had agreed, it was still obvious that he had treated you badly. So why would you still feel friendly towards him? Why would you want to see him again? Your -- your feeling for her explains everything, you see -- why you were embarrassed, and why you want to see the Dollmanns again."

"And why did you have to talk about Fräulein Dollmann?"

"There's nothing at Memmert," said Davies, "or von Brüning wouldn't have told us so much about it."

At last we had reached the heart of the matter.

"I know I haven't," said Davies quietly.

At last Davies spoke. "I don't know why you had to tell von Brüning everything. I just don't understand it."

"We can't explore the channels here any more," he said.

"I find it very difficult to talk about things like this," said Davies, without looking at me. "I should have told you before, but I couldn't. The truth is, I do like -- Clara, very much. And I think she likes me too." Our eyes met for a second, in which all was said that needed to be said. "But I'm sure she knows nothing about what her father's doing," he continued. "I'm sure she's got nothing to do with it. And I hoped we could avoid bringing her into it."

"Carruthers," said Davies seriously, "I realize you're trying to help, but I know she's completely innocent. I just know it. We mustn't involve her."

"No!" cried Davies. "We can't do that. My God! We can't let Dollmann carry on. He's a traitor, working for the Germans, against his own country!"

"Are you really sure?" I asked. "Don't you think she could be part of it? After all, you told me she encouraged you to follow them to Cuxhaven."

"Very well," I replied. "In that case, the best thing we can do is to forget the whole thing, and sail for England tonight."

"Of course we can't," I replied. "We've got to see him again. We've got to see both of them, in fact. And we must be friendly. You must tell the story you told today, and hope he believes it. Even if he doesn't, he won't dare say so, and we still have chances. And we must be friendly with them both."

Davies said nothing, but his face showed great pain. In the time we had been together, I had come to know Davies very well, and to understand how his honest mind worked. His strongest feeling was a deep love for his country, and a wish to serve her in any way he could. Now he had been given an unexpected chance to do something really important for his country, something that only he could do. But, at the same time, he loved Clara Dollmann, the daughter of a suspected traitor. It seemed that he could not take his great chance without hurting the woman he loved. It was a terrible position to be in.

"All right," I said. "I agree with you. We must go on with it. But we can't do so without involving her."

"Are you quite sure we can't?" he asked.

"Are you sure you wouldn't rather leave it and sail for England tonight?" I asked gently.

Davies didn't hesitate. "We can't do that. Perhaps there's some way we can stop Dollmann without involving her. If not, it can't be helped. We must go on with it."

We discussed Memmert for some time. I felt sure that the search for the Corinne 's gold was a way of hiding what was really happening on Memmert, but Davies disagreed. He still felt that the channels through the sands held the answer to the riddle. In the end, we decided that we would sail next day to Norderney, and we would make the next plan when we got there.