They came to the curving passageway that led into Santa Cruz. As they walked, their shadows joined along the whitewashed walls. It was strangely intimate, and Quart felt relieved when they emerged at the other end, into the night.

"Is that what you think?" she asked. "That I'm trying to seduce you?"

Quart didn't answer. They went on in silence by the wall, then turned down a narrow street that took them into the old Jewish quarter.

"Sir Marhalt also championed just causes," she said.

"Those were different times. Anyway, your Sir Marhalt was only a creation of John Steinbeck's. There are no just causes left. Even mine isn't one." He paused, as if reflecting on the truth of his words. "But it's my cause."

"You forget Father Ferro."

"His isn't a just cause. It's a personal choice. Everyone gets by as they can."

"Oh, please. I've seen Casablanca about twenty times. That's all I need, a priest playing the disillusioned hero. A priest who thinks he's Humphrey Bogart."

"I don't. I'm taller. Anyway, you're wrong. You know nothing about me." She walked on ahead, staring straight in front of her, as if she didn't want to hear. He wanted to take her by the arm and hold her back, but he stopped himself. "You don't know why I'm a priest, or why I'm here, or what I've done to be here," he said. "You don't know how many Priamo Ferros I've known in my life, nor how I dealt with them when I received orders." He spoke bitterly, knowing his words were useless. How could she understand?

She turned to face him and said, "It sounds as if you're sorry you don't have a head to send back to Rome in the next post." She moved towards him. "You thought it would be easy, didn't you? But I knew that things would be different once you got to know the victim."

"You're wrong," said Quart, holding her gaze. "My getting to know Father Ferro makes no difference, at least not on an official level."

"And what about unofficially?" She tapped her forehead. "You must have your own thoughts."

"That's my business. Anyway, I've known lots of my Victims', as you put it. And it made no difference."

Her sigh was contemptuous. "I suppose not. I suppose that's why you get to buy custom-made suits from smart tailors, wear expensive shoes and carry credit cards and a fantastic watch." She looked him up and down, provoking, hostile. "They must be your thirty pieces of silver."

She was angry, and Quart began to wonder how far she intended to go. They stood facing each other in a narrow street. Overhead, loaded with flowerpots, the balconies on either side almost touched.

"These clothes," Quart said, holding his lapel between two fingers, showing it to her, "and these shoes, and these credit cards, and this watch are very useful when you're trying to impress a Serbian general or an American diplomat. There are worker priests, married priests, priests who say Mass every morning, and priests like me. And I couldn't tell you who makes it possible for whom to exist." He smiled ironically, but his attention was elsewhere – Macarena was too near him, the street too narrow. "Although your Father Ferro and I agree on one thing; neither of us has any illusions about his job."

He stopped, suddenly afraid of his need to justify himself to her. They were alone in the street, lit by a distant streetlight. She looked lovely, her parted lips showing her white teeth. She breathed slowly, with the serenity of a woman who is beautiful and knows it. Her expression was no longer contemptuous. Quart felt a very real, physical, male fear, similar to vertigo. He had to make an effort not to step backward and rest against the wall. "Why won't you tell me what you know?" he asked.

She looked at him as if she'd expected something else. Her eyes moved to his dog collar. "You may not believe this, but I know very little," she answered finally. "I can guess at certain things. But I won't be the one to speak. You do your job, while others do theirs."

Quart set off up the narrow street. She followed in silence, clasping her leather rucksack to her chest.

Inside Las Teresas, hams hung among bottles of La Guita, old posters for Holy Week and the April feria, and faded photographs of slender, serious, long-dead bullfighters. At the bar, waiters wrote down customers' orders while Pepe, the manager, cut thin slices of Jabugo ham with a long razor-sharp knife, singing softly:

How pleased I am, dear cousin, how pleased I am to eat Serrano ham.

He addressed Quart's companion as Dona Macarena and, without either of them ordering anything, brought them tapas of pork in tomato sauce, pork sausage, grilled mushrooms, and two tall-stemmed glasses of fragrant, golden Manzanilla. By the door, leaning on the bar beside Quart, a regular with a red face was conscientiously downing one glass of wine after another. Pepe stopped singing occasionally and, still slicing ham, exchanged a few words with him about a football match soon to be played between Sevilla and Betis.

"Fantastic," the red-faced man said with drunken regularity. Pepe nodded and started singing again, and the man went back to his wine. A grey mouse poked its head from his jacket pocket. From time to time the man gave it little pieces of cheese from the plate beside him on the bar. The rodent diligently nibbled the cheese and nobody seemed in the least surprised.

Macarena sipped her Manzanilla. She rested an elbow on the bar confidently, as if she were at home. In fact, she moved through all of Santa Cruz as if it were part of her home; and in a way it was, or had been for centuries – every corner recorded in her genetic memory, known to her territorial instinct. Quart realised, and the realisation did nothing to calm the IEA agent, that he couldn't conceive of the district or the city without her presence, her black hair, her white teeth, her dark eyes. Once again he thought of the paintings of Romero de Torres, and the old tobacco factory that now housed the university. Carmen the cigarette girl, the damp tobacco leaves rolled against a tanned thigh. He looked up, and his eyes met hers, intent upon him.

"Do you like Seville?" Macarena asked.

"Very much," he said, wondering if she could guess his thoughts.

"It's a special place." She picked at their tapas. "The past and the present live here quite happily side by side. Gris says that we Sevillians are old and wise. We accept anything, and anything's possible." She glanced briefly at their neighbour with the red face and smiled. "Even sharing one's cheese in a bar with a mouse."

"Is your friend any good with computers?"

The look she gave him was almost admiring. "You never give up, do you?" she said, spearing a mushroom with a cocktail stick and eating it. "You have a one-track mind. Why don't you ask her?"

"I did. She was evasive, as you all are."

A man came in. He was fat, about fifty, and dressed in white. For a moment Quart thought he'd seen him somewhere before. The fat man raised his hat as he passed, looked around as if searching for someone, peered at his watch, then left by the other door, swinging a silver-handled walking stick. Quart noticed that the man's left cheek was red and covered with ointment, and that his moustache looked peculiar, as if it had been singed.

"What about the postcard?" Quart asked Macarena. "Does Gris Marsala have access to your great-aunt Carlota's trunk?"

She smiled, amused at his persistence. "She knows where it is, if that's what you mean. But it could just as easily have been Don Priamo. Or Father Oscar, or even me. Or my mother… Can you picture the duchess with her Coca-Cola, wearing a baseball cap back-to-front, hacking into the Vatican computer system in the wee hours?" She speared a piece of meat in tomato sauce and offered it to Quart. "I'm afraid your investigation may become absurd."

As Quart took the cocktail stick from Macarena, his fingers brushed hers. "I'd like to have a look at that trunk," he said.