Cooper had not taken his eyes off Tracy for an instant. He had waited for her next move. But it had not come. She had not gone near any of the paintings, nor had she made contact with an accomplice. All she had done was knock over an easel and spill some paints on the floor, but he was certain it had been done deliberately. But to what purpose? Somehow, Cooper felt that whatever had been planned had already happened. He looked around the walls of the salon. None of the paintings was missing.

Cooper hurried into the adjoining room. There was no one there but the guard and an elderly hunchback seated at his easel, copying the Clothed Maja. All the paintings were in place. But something was wrong. Cooper knew it.

He hurried back to the hara.s.sed director, whom he had met earlier. "I have reason to believe," Cooper blurted out, "that a painting has been stolen from here in the past few minutes."

Christian Machada stared at the wild-eyed American. "What are you talking about? If that were so, the guards would have sounded the alarm."

"I think that somehow a fake painting was subst.i.tuted for real one."

The director gave him a tolerant smile. "There is one small thing wrong with your theory, senor. It is not known to the general public, but there are sensors hidden behind each painting. If anyone tried to lift a painting from the wall--- which they would certainly have to do to subst.i.tute another painting--- the alarm would instantly sound."

Daniel Cooper was still not satisfied. "Could your alarm be disconnected?"

"No. If someone cut the wire to the power, that also would cause the alarm to go off. Senor, it is impossible for anyone to steal a painting from this museum. Our security is what you call proof from fools."

Cooper stood there shaking with frustration. Everything the director said was convincing. It did seem impossible. But then why had Tracy Whitney deliberately spilled those paints?

Cooper would not give up. "Humor me. Would you ask your staff to go through the museum and check to make sure nothing is missing? I'll be at my hotel."

There was nothing more Daniel Cooper could do.

At 7:00 that evening Christian Machada telephoned Cooper. "I have personally made an inspection, senor. Every painting is in its proper place. Nothing is missing from the museum."

So that was that. Seemingly, it had been an accident. But Daniel Cooper, with the instincts of a hunter, sensed that his quarry had escaped.

Jeff had invited Tracy to dinner in the main dining room of the Ritz Hotel.

"You're looking especially radiant this evening," Jeff complimented her.

"Thank you. I feel absolutely wonderful."

"It's the company. Come with me to Barcelona next week, Tracy. It's a fascinating city. You'd love---"

"I'm sorry, Jeff. I can't. I'm leaving Spain."

"Really?" His voice was filled with regret. "When?"

"In a few days."

"Ah. I'm disappointed."

You're going to be more disappointed, Tracy thought, when you learn I've stolen the Puerto. She wondered how he had planned to steal the painting. Not that it mattered any longer. I've outwitted clever Jeff Stevens. Yet, for some inexplicable reason Tracy felt a faint trace of regret.

Christian Machada was seated in his office enjoying his morning cup of strong black coffee and congratulating himself on what a success the prince's visit had been. Except for the regrettable incident of the spilled paints, everything had gone off precisely as planned. He was grateful that the prince and his retinue had been diverted until the mess could be cleaned up. The director smiled when he thought about the idiot American investigator who had tried to convince him that someone had stolen a painting from the Prado. Not yesterday, not today, not tomorrow, he thought smugly.

His secretary walked into the office. "Excuse me, sir. There is a gentleman to see you. He asked me to give you this."

She handed the director a letter. It was on the letterhead of the Kunsthaus Museum in Zurich: My Esteemed Colleague: This letter will serve to introduce Monsieur Henri Rendell, our senior art expert. Monsieur Rendell is making a tour of world museums and is particularly eager to see your incomparable collection. I would greatly appreciate any courtesies you extend him.

The letter was signed by the curator of the museum.

Sooner or later, the director thought happily, everyone comes to me.

"Send him in."

Henri Rendell was a tall, distinguished-looking, balding man with a heavy Swiss accent. When they shook hands, Machada noticed that the index finger on the right hand of his visitor was missing.

Henri Rendell said, "I appreciate this. It is the first opportunity I have had to visit Madrid, and I am looking forward to seeing your renowned works of art."

Christian Machada said modestly, "I do not think you will be disappointed, Monsieur Rendell. Please come with me. I shall personally escort you."

They moved slowly, walking through the rotunda with its Flemish masters, and Rubens and his followers, and they visited the central gallery, filled with Spanish masters, and Henri Rendell studied each painting carefully. The two men spoke as one expert to another, evaluating the various artists' style and perspective and color sense.

"Now," the director declared, "for the pride of Spain." He led his visitor downstairs, into the gallery filled with Goyas.

"It is a feast for the eyes!" Rendell exclaimed, overwhelmed. "Please! Let me just stand and look."

Christian Machada waited, enjoying the man's awe.

"Never have I seen anything so magnificent," Rendell declared. He walked slowly through the salon, studying each painting in turn. "The Witches' Sabbath," Rendell said. "Brilliant!"

They moved on.

"Goya's Self-Portrait--- fantastic!"

Christian Machada beamed.

Rendell paused in front of the Puerto. "A nice fake." He started to move on.

The director grabbed his arm. "What? What was it you said, senor?"

"I said it is a nice fake."

"You are very much mistaken." He was filled with indignation.

"I do not think so."

"You most certainly are," Machada said stiffly. "I a.s.sure you, it is genuine. I have its provenance."

Henri Rendell stepped up to the picture and examined it more closely. "Then its provenance has also been faked. This was done by Goya's disciple, Eugenio Lucas y Padilla. You must be aware, of course, that Lucas painted hundreds of fake Goyas."

"Certainly I am aware of that," Machada snapped. "But this is not one of them."

Rendell shrugged. "I bow to your judgment." He started to move on.

"I personally purchased this painting. It has pa.s.sed the spectrograph test, the pigment test---"

"I do not doubt it. Lucas painted in the same period as Goya, and used the same materials." Henri Rendell bent down to examine the signature at the bottom of the painting. "You can rea.s.sure yourself very simply, if you wish. Take the painting back to your restoration room and test the signature." He chuckled with amus.e.m.e.nt. "Lucas's ego made him sign his own paintings, but his pocketbook forced him to forge Goya's name over his own, increasing the price enormously." Rendell glanced at his watch. "You must forgive me. I'm afraid I am late for an engagement. Thank you so much for sharing your treasures with me."

"Not at all," the director said coldly. The man is obviously a fool, he thought.

"I am at the Villa Magna, if I can be of service. And thank you again, senor." Henri Rendell departed.

Christian Machada watched him leave. How dare that Swiss idiot imply that the precious Goya was a fake!

He turned to look at the painting again. It was beautiful, a masterpiece. He leaned down to examine Goya's signature. Perfectly normal. But still, was it possible? The tiny seed of doubt would not go away. Everyone knew that Goya's contemporary, Eugenio Lucas y Padilla, had painted hundreds of fake Goyas, making a career out of forging the master. Machada had paid $3.5 million for the Goya Puerto. If he had been deceived, it would be a terrible black mark against him, something he could not bear to think about.

Henri Rendell had said one thing that made sense: There was, indeed, a simple way to ascertain its authenticity. He would test the signature and then telephone Rendell and suggest most politely that perhaps he should seek a more suitable vocation.

The director summoned his a.s.sistant and ordered the Puerto moved to the restoration room.

The testing of a masterpiece is a very delicate operation, for if it is done carelessly, it can destroy something both priceless and irreplaceable. The restorers at the Prado were experts. Most of them were unsuccessful painters who had taken up restoration work so they could remain close to their beloved art. They started as apprentices, studying under master restorers, and worked for years before they became a.s.sistants and were allowed to handle masterpieces, always under the supervision of senior craftsmen.

Juan Delgado, the man in charge of art restoration at the Prado, placed the Puerto on a special wooden rack, as Christian Machada watched.

"I want you to test the signature," the director informed him.

Delgado kept his surprise to himself. "Si, Senor Director."

He poured isopropyl alcohol onto a small cotton ball and set it on the table next to the painting. On a second cotton ball he poured petroleum distillate, the neutralizing agent.

"I am ready, senor."

"Go ahead then. But be careful!"

Machada found that it was suddenly difficult for him to breathe. He watched Delgado. lift the first cotton ball and gently touch it to the G in Goya's signature. Instantly, Delgado picked up the second cotton ball and neutralized the area, so that the alcohol could not penetrate too deeply. The two men examined the canvas.

Delgado was frowning. "I'm sorry, but I cannot tell yet," he said. "I must use a stronger solvent."

"Do it," the director commanded.

Delgado opened another bottle. He carefully poured dimenthyl petone onto a fresh cotton ball and with it touched the first letter of the signature again, instantly applying the second cotton ball. The room was filled with a sharp, pungent odor from the chemicals. Christian Machada stood there staring at the painting, unable to believe what he was seeing. The G in Goya's name was fading, and in its place was a clearly visible L.

Delgado turned to him, his face pale. "Shall--- shall I go on?"

"Yes," Machada said hoa.r.s.ely. "Go on."

Slowly, letter by letter, Goya's signature faded under the application of the solvent, and the signature of Lucas materialized. Each letter was a blow to Machada's stomach. He, the head of one of the most important museums in the world, had been deceived. The board of directors would hear of it; the King of Spain would hear of it; the world would hear of it. He was ruined.

He stumbled back to his office and telephoned Henri Rendell.

The two men were seated in Machada's office.

"You were right," the director said heavily. "It is a Lucas. When word of this gets out, I shall be a laughing stock."

"Lucas has deceived many experts," Rendell said comfortingly. "His forgeries happen to be a hobby of mine."

"I paid three and a half million dollars for that painting."

Rendell shrugged. "Can you get your money back?"

The director shook his head in despair. "I purchased it directly from a widow who claimed it had been in her husband's family for three generations. If I sued her, the case would drag on through the courts and it would be bad publicity. Everything in this museum would become suspect."

Henri Rendell was thinking hard. "There is really no reason for the publicity at all. Why don't you explain to your superiors what has happened, and quietly get rid of the Lucas? You could send the painting to Sotheby's or Christie's and let them auction it off."

Machada shook his head. "No. Then the whole world would learn the story."

Rendell's face brightened. "You may be in luck. I might have a client who would be willing to purchase the Lucas. He collects them. He is a man of discretion."

"I would be glad to get rid of it. I never want to see it again. A fake among my beautiful treasures. I'd like to give it away," he added bitterly.

"That will not be necessary. My client would probably be willing to pay you, say, fifty thousand dollars for it. Shall I make a telephone call?"

"That would be most kind of you, Senor Rendell."

At a hastily held meeting the stunned board of directors decided that the exposure of one of the Prado's prize paintings as a forgery had to be avoided at any cost. It was agreed that the prudent course of action would be to get rid of the painting as quietly and as quickly as possible. The dark-suited men filed out of the room silently. No one spoke a word to Machada, who stood there, sweltering in his misery.

That afternoon a deal was struck. Henri Rendell went to the Bank of Spain and returned with a certified check for $50,000, and the Eugenio Lucas y Padilla was handed over to him, wrapped in an inconspicuous piece of burlap.

"The board of directors would be very upset if this incident were to become public," Machada said delicately, "but I a.s.sured them that your client is a man of discretion."

"You can count on it," Rendell promised.

When Henri Rendell left the museum, he took a taxi to a residential area in the northern end of Madrid, carried the canvas up some stairs to a third-floor apartment, and knocked on the door. It was opened by Tracy. In back of her stood Cesar Porretta. Tracy looked at Rendell questioningly, and he grinned: "They couldn't wait to get this off their handsl" Henri Rendell gloated.

Tracy hugged him. "Come in."

Porretta took the painting and placed it on a table.

"Now," the hunchback said, "you are going to see a miracle--- a Goya brought back to life."

He reached for a bottle of mentholated spirits and opened it. The pungent odor instantly filled the room. As Tracy and Rendell looked on, Porretta poured some of the spirits onto a piece of cotton and very gently touched the cotton to Lucas's signature, one letter at a time. Gradually the signature of Lucas began to fade. Under it was the signature of Goya.

Rendell stared at it in awe. "Brilliant!"

"It was Miss Whitney's idea," the hunchback admitted. "She asked whether it would be possible to cover up the original artist's signature with a fake signature and then cover that with the original name."

"He figured out how it could be done," Tracy smiled.