“My people may worry about me,” Alex said.

“From what I know of Mr Blunt and his colleagues in London, that is unlikely. But it’s unimportant. By the time they begin to ask questions, it will be too late.”

Too late? Why? Alex realized he was still completely in the dark.

“The Casa de Oro is fenced all around. The fence is electrified. There is only one entrance and it is well guarded. Do not attempt to escape, Alex. If you do, you may be shot and that is not at all what I have planned. After today, I’m afraid I will be moving you to new quarters. As you may well be aware, I have important guests arriving and it would be better for you to ‘have your own space’ as I believe you say. You are still welcome to use the house, the pool, the grounds. But I would ask you to remain invisible. My guests speak very little English so there is no point approaching them. If you cause me any embarrassment, I will have you whipped.”

General Sarov reached forward and pronged a slice of pineapple.

“But that’s enough of this unpleasantness,” he said. “We have the whole morning together. Do you ride?”

Alex hesitated. He didn’t like horse-riding. “I have ridden,” he said.

“Excellent.”

Alex helped himself to some melon. “I asked you last night what you wanted with me,” he said. “You still haven’t given me a reply.”

“All in good time, Alex. All in good time.”

After breakfast, they walked out into the open air. Now Alex understood how the house had got its name. It was made of some sort of pale yellow brick that, with the sun beating down, really did look gold. Although the house was only two storeys high, it was spread over a vast area, with wide stone steps leading down to a formal garden. Blunt had described it as a palace, but it was more elegant than majestic with slender doors and windows, more archways and finely carved balustrades. Looking at the house, it was as if nothing had changed since the early nineteenth century when it had been built. But there were also armed guards on patrol. There were alarm bells and a series of spotlights mounted on metal brackets. Ugly reminders of the modern age.

They continued over to a stable block where a man was waiting with two magnificent horses; a white stallion for Sarov, a smaller grey for Alex. Riding was the one sport that Alex had never enjoyed. The last time he had got onto a horse it had almost killed him, and it was with reluctance that he took hold of the reins and swung himself into the saddle. Out of the comer of his eye he saw Sarov do the same and knew at once that the Russian was an expert, in total control of his steed.

They rode out together, Alex trying to keep his balance and not look too out of control. Fortunately, his horse seemed to know where they were going.

“This was a sugar farm once,” Sarov explained, repeating what Troy had already told him. “Slaves worked here. There were almost a million slaves in Cuba and Cayo Esqueleto.” He pointed at the tower. “That was the watch tower. They would ring a bell there at half past four in the morning for the slaves to start work. They were brought here from West Africa. They worked here. And they died here.”

They passed close to a low, rectangular building some way from the main house. Alex noticed that the single door and all the windows were barred?

“That is the barracon,” Sarov said. “The house of slaves. Two hundred of them slept in there, penned in like animals. If we have time, I will show you the punishment block. We still have the original stocks. Can you imagine, Alex, being fastened by your ankles for weeks, or even months at a time? Unable to move. Starving and thirsty…”

“I don’t want to imagine it,” Alex said.

“Of course not. The Western world prefers to forget the crimes that made it rich.”

Alex was relieved when they broke into a canter. At least it meant there was no further need to talk. They followed a dirt track that brought them to the edge of the sea. Looking down, Alex could see where Garcia’s boat had been moored the day before. It reminded him of the true nature of the man he was with. Sarov was being friendly. He evidently enjoyed having Alex as his guest. But he was a killer. And a killer with a nuclear bomb.

They came to the end of the track and continued more slowly now, with the sea on their right.

The Casa de Oro had disappeared behind them.

“I wish to tell you something about myself,” Sarov said suddenly. “In fact, I will tell you more than I have ever told anyone else.”

He rode on for a few moments in silence.

“I was born in 1940,” he began. “This was during the Second World War, the year before the Germans attacked my country. Perhaps that is why I have always been a patriot, why I have always thought my country should come first. I have spent much of my life serving it. In the army, fighting for what I believe in. I still believe I am serving it now.”

He reined in his horse and turned to Alex, who had stopped beside him.

“I got married when I was thirty. A year later, my wife gave me something I had always wanted. A son. His name was Vladimir and from the moment he drew his first breath he was the best thing in my life. He grew into a handsome boy, and let me tell you, no father could have been prouder than I was of him. He did well at school, top in almost every class. He was a first-class athlete. I think he could one day have competed at Olympic level. But that was not to be…”

Alex already knew the end of this story. He remembered what Blunt had told him.

“I believed it was right for Vladimir to serve his country, just as I had,” Sarov went on. “I wanted him to join the army. His mother disagreed. Unfortunately, that disagreement ended our marriage.”

“You asked her to leave?”

“No. I didn’t ask her to leave. I ordered her to. She departed from my house and I never saw her again. And Vladimir did join the army. This was in 1988 when he was sixteen years old. He was flown to Afghanistan where we were fighting a hard, difficult war. He had been there for just three weeks when he was sent to reconnoitre a village as part of a patrol. A sniper shot him and he died.”

Sarov’s voice cracked briefly and he stopped. But a moment later he continued in a careful, measured tone.

“The war ended a year later. Our government, weak and cowardly, had lost the spirit to fight. We withdrew. The whole thing had been for nothing. And this is what you must understand. This is the truth. There is nothing more terrible in this world than for a father to lose his son.” He took a breath. “I believed I had lost Vladimir for ever. Until I met you.”

“Me?” Alex was almost too startled to speak.

“You are just two years younger than Vladimir was when he died. But you have so much in common with him, Alex-even though you were brought up on the other side of the world! There is, first, a very slight resemblance. But it is not just your physical appearance. You too are serving your country. Fourteen years old and a spy! How rare it is to find any young person who is prepared to fight for his beliefs!”

“Well, I wouldn’t go that far,” Alex muttered.

“You have courage. That business at the sugar factory and in the cave would prove it even if your track record didn’t speak volumes more. You speak many languages and one day, soon, you could learn Russian. You ride, you dive, you fight, and you aren’t scared. I have never met a boy like you. Except one. You are like my Vladimir, Alex, and that is what I hope you will become.”

“What are you getting at?” Alex asked. They still weren’t moving and he was beginning to feel the heat of the sun. The horse was sweating and attracting flies. The sea was a long way beneath them and none of its breeze was reaching them.

“Isn’t it obvious? I’ve read your file. You have grown up on your own. You had an uncle but you didn’t even know what he was until he died. You have no parents. I have no son. We are both alone.”