"How long have you been doing this?"

"Oh, not long. Three, four years." She turned to her daughter, trying to remember exactly. "I've always been very curious; if I see a line of print, I just have to start reading… One day Macarena bought a computer for her work. When she went out, I'd sit at it, awestruck. There was a game, a little ping-pong ball – that's how I learned my way around the keyboard. I have trouble sleeping, as you know, so I ended up spending quite a few hours at the computer. I think I became addicted."

"At her age," said Macarena affectionately.

"Yes." The old lady faced Quart, as if inviting him to express his disapproval. "I was so curious that I began to read everything I could find about computers. I learned English when I was a child, so I signed up for correspondence courses and subscribed to computer magazines." She gave a little laugh and covered her mouth with her hand, as if shocked at herself. "My health isn't too good, but luckily my brain's still all right. I became a bit of an expert in quite a short time. And I assure you, at my age, that's exhilarating."

"She even fell in love," said Macarena.

Mother and daughter laughed. Quart wondered if they weren't both slightly crazy; it all seemed like a big joke. Or maybe he was the one who was going mad. This city's gone to your head, he told himself. Just as well that you're leaving now, before it's too late.

"She's exaggerating," said Cruz Bruner. "I had the equipment, the software, so I started to get around. And, well, yes, I did have a virtual love affair. One night I happened to get into a hacker's computer, a young man of sixteen… You should see your face, Father. I've never seen anyone look so astonished."

"You can't expect me to find this normal."

"No, I suppose not." The old lady motioned at the modem and the pile of magazines. "Imagine," she said, "what it was for a woman of almost seventy to discover such a world. My friend called himself Mad Mike. I'll never hear Mike's voice or see his face, but he led me all over this fascinating world. There was an electronic bulletin board, and that's how I came into contact with other addicts, often boys who spent hours up in their rooms getting into other people's computers."

She sounded proud, as if talking about a highly exclusive club. Quart needed no explanations, but he must still have been looking puzzled, because Macarena smiled and told her mother to explain to him what an electronic bulletin board was.

The old lady put a hand on the keyboard. "People post messages and talk. There are chat rooms, too. After a while you reach a certain level in the hacker world. When you call the first time, they ask you for your name and telephone number. You don't give them your real name but an alias and a false number. A certain amount of paranoia is a good quality in a hacker."

"What's your alias?"

"Do you really want to know? It's against the rules, but I'll tell you, since you've got this far, thanks to Macarena." She held up her head with mock pride. "I'm Queen of the South."

Things were happening on the monitor, and the duchess broke off to press a few keys. A long text, in small type, appeared on screen. Cruz Bruner went on. "After that," she said, "I started to visit secret Websites on the Internet. I made friends there. It's great fun. You swap useful tips, tricks, games, viruses. Gradually I learned how to get into all the networks, travel abroad, hide my entry and exit points, get into protected systems. My happiest day was breaking into the Ayuntamiento and changing my tax bill."

"Which is a crime," her daughter said, scolding, and obviously not for the first time. "When I found out, I ran to city hall. Our bill was entered as having been paid until 2005! I had to tell them it was an error."

"It may be a crime," conceded the old lady, "but it doesn't seem like a crime from here. Nothing does." She smiled at Quart mischievously. "That's the wonderful thing. Now," she went on, "I keep in frequent touch with Mike as well as twenty or so other hackers. Most of them are probably under twenty. I don't know their ages,' genders, or real names, but we have terribly exciting virtual meetings in places like the Gaieties Lafayette in Paris, the Imperial War Museum, or branches of the Confederation of Russian Banks… Which, by the way, is so vulnerable that even a child could get in and alter the accounts. The Confederation tends to be used as a training route for novice hackers."

She was Vespers, there was no doubt about it. Quart could see her crouched over her computer night after night, travelling through cyberspace, meeting other solitary travellers on her journey. Unexpected meetings, exchanges of information and dreams, the excitement of violating secrets and crossing the boundary into the forbidden – a secret fraternity for whom time, space, memory, solitude, success or failure had no meaning, who had created a virtual world in which everything was possible and nothing was subject to laws. A wonderful escape route of infinite possibilities. In her own way, Cruz Bruner too was rebelling against the Seville embodied by the handsome man in the hall portrait, beside the painting of the fair young girl by Zuloaga.

"How did you get into the Vatican?"

"By chance. A contact in Rome, Deus ex Machina – I suspect he's a seminarian or a young priest – had wandered about the edges of the system, for fun. We became friends, and he gave me a couple of good pathways. That was about six or seven months ago. The situation at Our Lady of the Tears was just then becoming serious. Neither the archbishop of Seville nor the nunciature in Madrid would take any notice of Father Ferro, and it occurred to me that this would be a good way of getting Rome's attention."

"Did you tell Father Ferro?"

"No. I didn't even let my daughter know. She found out later, when the existence of Vespers – as you called him – became known." The old lady pronounced the name with obvious satisfaction. Quart would have liked to see the faces of His Eminence Jerzy Iwaszkiewicz and Monsignor Spada hearing all this. "At first, I thought I'd leave a simple message in the central Vatican system, hoping it would reach the right quarters. It was only later, when I found my way around, that I thought of getting through to the Pope's computer. By chance I came across a well-protected file called INMAVAT and I realised there was something important there. I made a couple of attempts to get in, using some tricks taught me by my hacker friends, and one night I succeeded. For a week I visited INMAVAT until I understood what it was all about. I found what I wanted, gathered my ammunition, and began my attack. You know the rest." "Who sent me the postcard?"

"Oh that. I did, of course. Since you were here, I thought you ought to see the other side of the problem. I went up to the pigeon loft and found something suitable in Carlota's trunk. It was slightly bizarre, but it had the desired effect."

Despite himself, Quart burst out laughing. "How did you get into my hotel room?"

The old lady looked shocked. "Heavens, I didn't do it myself," she said. "Can you see me tiptoeing along hotel corridors? I used a more dignified method. My maid slipped a waitress some money." She half-turned to her daughter. "When you showed Macarena the postcard, she knew immediately it was I. But she was nice enough not to tell."

Quart found confirmation in Macarena's eyes. He glanced at the computer screen. "Tell me what you're up to now."

"Oh, this. You could call it a final settling of scores. Don't be alarmed. It has nothing to do with Rome this time. Something closer to home. More personal."

Quart took a look. S amp;B Confidential, he read. Summary of CB internal investigation re PT deal and others. The names of the Cartujano Bank and Pencho Gavira stood out in the text: