Since no one had told him to sit down, El Potro stood, as if on duty, and nodded. "Exactly," he said.

"Which way did the lovebirds go?" asked Don Ibrahim, placing the panama on his head.

El Potro glanced down the street and said they were heading toward the Arenal; plenty of time to catch up with them.

Don Ibrahim took the camera from La Nina's lap and handed it to him. "Go on, take out the film before it spoils."

Obediently, manoeuvring with both "his good arm and the one in the sling, El Potro opened the camera while Don Ibrahim searched for the other roll of film. At last he found it, took it out of its box, and handed it to his associate. "You did rewind it, didn't you?" he asked casually. "Before opening the camera?"

El Potro, very still, stared at Don Ibrahim. Suddenly he snapped shut the camera. "What was it I was supposed to rewind?" he asked suspiciously, arching an eyebrow.

Holding the new film in one hand and his cigar in the other, Don Ibrahim looked at him for some time. "Shit," he said.

They walked in silence to the Arenal. Macarena turned to look at Quart from time to time, but neither of them spoke. There wasn't much to say and he couldn't ask whether the encounter with her husband had been an accident or planned by her. He would probably never know, he thought.

"This is the way he went," Macarena said at last, when they came to the river.

They descended wide steps that led to the quays of the Guadalquivir, at the foot of the ancient Arab tower named Torre del Oro. There wasn't the slightest breeze, and the shadows of the palms, jacarandas, and bougainvilleas were motionless in the moonlight.

"Who?" he asked.

"Captain Xaloc."

Dark and still, tourist boats were moored to pontoons along the deserted bank. The black water reflected the lights of Triana on the opposite side, bounded by strings of car headlights on the Isabel II and San Telmo bridges.

"This was Seville's old port," said Macarena. She wore her jacket round her shoulders and still clutched her leather bag to her chest. "Only a century ago, there would have been ships docking here… The remains of the great trade with America. Ships sailed down the river to Sanlucar, then Cadiz, before crossing the Atlantic." She walked forward and stopped by a flight of steps leading down to the dark water. "Old photographs show all kinds of vessels – brigantines, schooners, skiffs – moored on both banks… Over there were the fishermen's boats, and boats with white awnings that brought the cigarette girls over from Triana to the tobacco factory. All the cranes and the warehouses were here on this quay."

She fell silent, turning towards the Paseo del Arenal, the dome of the Maestranza Theatre, the modern buildings that stood between them and the tower of La Giralda, lit up in the distance, and Santa Cruz, hidden from view.

"It was a forest of masts and sails," she added. "That was what Carlota saw from the pigeon loft."

They walked along the quay in the shadows cast by the trees in the moonlight. A young couple was kissing in the light of a street-lamp, and Quart saw Macarena watching them with a thoughtful smile.

"You are nostalgic," he said, "for a Seville you've never known."

Her smile widened, then her face was again in shadow. "That's not true," she said. "I knew it well, and still do. I've read and dreamed a lot about this city. Some things my grandfather and mother told me. Others I simply knew instinctively." She touched her wrist, where her pulse beat. "I feel them here."

"Why did you choose Carlota Bruner?"

Macarena took a moment to answer. "She chose me." She turned to Quart. "Do priests believe in ghosts?"

"Not really. Ghosts don't stand up to electric light or nuclear power… Or to computers."

"Maybe that's their charm. I believe in them, or at least in a certain type of ghost. Carlota was a romantic young woman who read novels. She lived wrapped in cotton wool in an artificial world, protected from everything. One day she met a man. A real man. It was as if she'd been struck by lightning. Unfortunately, Manuel Xaloc fell in love with her too."

Occasionally they passed the motionless shadow of someone fishing from the quay, the ember of a cigarette, a glint of light at the end of a rod and line, a splash in the calm waters. A fish flapped on the paving stones of the quay, gleaming in the moonlight until a hand returned it to the bucket.

"Tell me about Xaloc," said Quart.

"He was thirty years old and poor, a second officer on one of the steamers that sailed between Seville and Sanlucar. They met when Carlota took a journey downriver with her parents. They say that he was also handsome, and I imagine that his uniform added to his looks. You know that's often true of sailors, soldiers…"

She seemed about to add something but left the sentence unfinished. They passed a tourist boat moored to the quay, black and silent. Quart managed to make out its name in the moonlight: LOVELY.

Macarena went on. "Xaloc was caught lurking by the railings of the Casa del Postigo, and my great-grandfather Luis had him fired. He also used all his influence, and it was considerable, to make sure that the man didn't get a job anywhere else. Desperate, Xaloc decided to go to America to seek his fortune. Carlota promised she would wait for him. It's the perfect plot for a romantic novel, don't you think?"

They walked side by side, and once again their steps occasionally brought them so close together that they almost touched. Suddenly Macarena stepped around an iron bollard in the darkness, and she was right next to Quart, brushing his side for the first time. She seemed to take an age to move away.

"Xaloc boarded his ship here," she said. "A schooner called the Nausica. Carlota wasn't even allowed to come and say goodbye. From the pigeon loft she watched the ship sail down the river; it wouldn't have been possible for her to see him from so far away, but she claimed he was on deck, waving a handkerchief until the boat was out of sight."

"How did things go for Xaloc?"

"Well. After a time he was given command of a ship and smuggled goods between Mexico, Florida and Cuba." There was a hint of admiration in her voice. Quart could picture Manuel Xaloc on the bridge of a ship, a column of smoke on the horizon. "They say he wasn't exactly a saint, that he also did some pirating. Some of the ships that crossed his path sank without trace, or were found mysteriously adrift, plundered. I suppose he was in a hurry to make his fortune and return… For six years he sailed the Caribbean and he acquired quite a reputation. The Americans put a price on his head. One day, out of the blue, he landed in Seville with a fortune in banknotes and gold coins and a velvet bag that contained twenty wonderful pearls for their wedding."

"Even though he'd never heard from her?"

"Yes. I suppose Xaloc was a romantic too. He assumed that my great-grandfather had prevented Carlota from writing and he had faith in her love, and in a way he was right. She told him she'd wait for him, and she was still waiting in the tower, watching the river." Macarena stared at the black current. "She had gone mad two years before his return."

"Did they get to see each other?"

"Yes. My great-grandfather was devastated. At first he refused. He was an arrogant man and blamed Xaloc for the misfortune. In the end, on the advice of doctors and his wife's pleas, he agreed to a meeting. The captain came one afternoon to the courtyard that you know, in his merchant navy uniform: navy blue, gilt buttons… You can picture the scene, can't you? His skin was weathered by the sun, and his moustache and sideburns had turned grey. They say he looked twenty years older than he was. Carlota didn't recognise him. After ten minutes a clock struck and she said, 'I must go to the tower. He may return at any time.' And she left."