Every year, on the first Saturday in June, the Count de Matigny sponsored a charity ball for the benefit of the Children's Hospital in Paris. Tickets for the white-tie affair were a thousand dollars apiece, and society's elite flew in from all over the world to attend.

The Ch��teau de Matigny, at Cap d'Antibes, was one of the showplaces of France. The carefully manicured grounds were superb, and the ch��teau itself dated back to the fifteenth century. On the evening of the fete, the grand ballroom and the petit ballroom were filled with beautifully dressed guests and smartly liveried servants offering endless glasses of champagne. Huge buffet tables were set up, displaying an astonishing array of hors d'oeuvres on Georgian silver platters.

Tracy, looking ravishing in a white lace gown, her hair dressed high and held in place by a diamond tiara, was dancing with her host, Count de Matigny, a widower in his late sixties, small and trim, with pale, delicate features. The benefit ball the count dives each year for the Children's Hospital is a racket. Gunther Hartog had told Tracy. Ten percent of the money goes to the children  -  ninety percent goes into his pocket.

"You are a superb dancer, Duchess," the count said.

Tracy smiled. "That's because of my partner."

"How is it that you and I have not met before?"

"I've been living in South America," Tracy explained. "In the jungles, I'm afraid."

"Why on earth!"

"My husband owns a few mines in Brazil."

"Ah. And is your husband here this evening?"

"No. Unfortunately, he had to stay in Brazil and take care of business."

"Unlucky for him. Lucky for me." His arm tightened around her waist. "I look forward to our becoming very good friends."

"And I, too," Tracy murmured.

Over the count's shoulder Tracy suddenly caught sight of Jeff Stevens, looking suntanned and ridiculously fit. He was dancing with a beautiful, willowy brunet in crimson taffeta, who was clinging to him possessively. Jeff saw Tracy at the same moment and smiled.

The bastard has every reason to smile, Tracy thought grimly. During the previous two weeks Tracy had meticulously planned two burglaries. She had broken into the first house and opened the safe, only to find it empty. Jeff Stevens had been there first. On the second occasion Tracy was moving through the grounds toward the targeted house when she heard the sudden acceleration of a car and caught a glimpse of Jeff as he sped away. He had beaten her to it again. He was infuriating. Now he's here at the house I'm planning to burgle next, Tracy thought.

Jeff and his partner danced nearer. Jeff smiled and said, "Good evening, Count."

The Count de Matigny smiled. "Ah, Jeffrey. Good evening. I'm so pleased that you could come."

"I wouldn't have missed it." Jeff indicated the voluptuous-looking woman in his arms. "This is Miss Wallace. The Count de Matigny."

"Enchant��!" The count indicated Tracy. "Duchess, may I present Miss Wallace and Mr. Jeffrey Stevens? The Duchess de Larosa."

Jeff's eyebrows raised questioningly. "Sorry. I didn't hear the name."

"De Larosa," Tracy said evenly.

"De Larosa... De Larosa." Jeff was studying Tracy. "That name seems so familiar. Of course! I know your husband. Is the dear fellow here with you?"

"He's in Brazil." Tracy found that she was gritting her teeth.

Jeff smiled. "Ah, too bad. We used to go hunting together. Before he had his accident, of course."

"Accident?" the count asked.

"Yes." Jeff's tone was rueful. "His gun went off and shot him in a very sensitive area. It was one of those stupid things." He turned to Tracy. "Is there any hope that he'll ever be normal again?"

Tracy said tonelessly, "I'm sure that one day he'll be as normal as you are, Mr. Stevens."

"Oh, good. You will give him my best regards when you talk to him, won't you, Duchess?"

The music stopped. The Count de Matigny apologized to Tracy. "If you'll excuse me, my dear, I have a few hostly duties to attend to." He squeezed her hand. "Don't forget you're seated at my table."

As the count moved away, Jeff said to his companion, "Angel, you put some aspirin in your bag, didn't you? Could you get one for me? I'm afraid I'm getting a terrible headache."

"Oh, my poor darling." There was an adoring look in her eyes. "I'll be right back, sweetheart."

Tracy watched her slink across the floor. "Aren't you afraid she'll give you diabetes?"

"She is sweet, isn't she? And how have you been lately, Duchess?"

Tracy smiled for the benefit of those around them. "That's really none of your concern, is it?"

"Ah, but it is. In fact, I'm concerned enough to give you some friendly advice. Don't try to rob this ch��teau."

"Why? Are you planning to do it first?"

Jeff took Tracy's arm and walked her over to a deserted spot near the piano, where a dark-eyed young man was soulfully massacring American show tunes.

Only Tracy could hear Jeff's voice over the music. "As a matter of fact, I was planning a little something, but it's too dangerous."

"Really?" Tracy was beginning to enjoy the conversation.

It was a relief to be herself, to stop playacting. The Greeks had the right word for it, Tracy thought. Hypocrite was from the Greek word for "actor."

"Listen to me, Tracy." Jeff's tone was serious. "Don't try this. First of all, you'd never get through the grounds alive. A killer guard dog is let loose at night."

Suddenly, Tracy was listening intently. Jeff was planning to rob the place.

"Every window and door is wired. The alarms connect directly to the police station. Even if you did manage to get inside the house, the whole place is crisscrossed with invisible infrared beams."

"I know all that." Tracy was a little smug.

"Then you must also know that the beam doesn't sound the alarm when you step into it. It sounds the alarm when you step out of it. It senses the heat change. There's no way you can get through it without setting it off."

She had not known that. How had Jeff learned of It?

"Why are you telling me all this?"

He smiled, and she thought he had never looked more attractive. "I really don't want you to get caught, Duchess. I like having you around. You know, Tracy, you and I could become very good friends."

"You're wrong," Tracy assured him. She saw Jeff's date hurrying toward them. "Here comes Ms. Diabetes. Enjoy yourself."

As Tracy walked away, she heard Jeff's date say, "I brought you some champagne to wash it down with, poor baby."

The dinner was sumptuous. Each course was accompanied by the appropriate wine, impeccably served by white-gloved footmen. The first course was a native asparagus with a white truffle sauce, followed by a consomm�� with delicate morels. After that came a saddle of lamb with an assortment of fresh vegetables from the count's gardens. A crisp endive salad was next. For dessert there were individually molded ice-cream servings and a silver epergne, piled high with petite fours. Coffee and brandy came last. Cigars were offered to the men, and the women were given Joy perfume in a Baccarat crystal flacon.

After dinner, the Count de Matigny turned to Tracy. "You mentioned that you were interested in seeing some of my paintings. Would you like to take a look now?"

"I'd love to," Tracy assured him.

The picture gallery was a private museum filled with Italian masters, French Impressionists, and Picassos. The long hall was ablaze with the bewitching colors and forms painted by immortals. There were Monets and Renoirs, Canalettos and Guardis and Tintorettos. There was an exquisite Tiepolo and Guercino and a Titian, and there was almost a full wall of C��zannes. There was no calculating the value of the collection.

Tracy stared at the paintings a long time, savoring their beauty. "I hope these are well guarded."

The count smiled. "On three occasions thieves have tried to get at my treasures. One was killed by my dog, the second was maimed, and the third is serving a life term in prison. The ch��teau is an invulnerable fortress, Duchess."

"I'm so relieved to hear that, Count."

There was a bright flash of light from outside. "The fireworks display is beginning," the count said. "I think you'll be amused." He took Tracy's soft hand in his papery, dry one and led her out of the picture gallery. "I'm leaving for Deauville in the morning, where I have a villa on the sea. I've invited a few friends down next weekend. You might enjoy it."

"I'm sure I would," Tracy said regretfully, "but I'm afraid my husband is getting restless. He insists that I return."

The fireworks display lasted for almost an hour, and Tracy took advantage of the distraction to reconnoiter the house. What Jeff had said was true: The odds against a successful burglary were formidable, but for that very reason Tracy found the challenge irresistible. She knew that upstairs in the count's bedroom were $2 million in jewels, and half a dozen masterpieces, including a Leonardo.

The ch��teau is a treasure house, Gunther Hartog had told her, and it's guarded like one. Don't make a move unless you have a foolproof plan.

Well, I've worked out a plan, Tracy thought. Whether it's foolproof or not, I'll know tomorrow.

The following night was chilly and cloudy, and the high walls around the ch��teau appeared grim and forbidding as Tracy stood in the shadows, wearing black coveralls, gum-soled shoes, and supple black kid gloves, carrying a shoulder bag. For an unguarded moment Tracy's mind embraced the memory of the walls of the penitentiary, and she gave an involuntary shiver.

She had driven the rented van alongside the stone wall at the back of the estate. From the other side of the wall came a low, fierce growl that developed into a frenzied barking, as the dog leapt into the air, trying to attack. Tracy visualized the Doberman's powerful, heavy body and deadly teeth.

She called out softly to someone in the van, "Now."

A slight, middle-aged man, also dressed in black, with a rucksack on his back, came out of the van holding onto a female Doberman. The dog was in season, and the tone of barking from the other side of the stone wall suddenly changed to an excited whine.

Tracy helped lift the bitch to the top of the van, which was almost the exact height of the wall.

"One, two, three," she whispered.

And the two of them tossed the bitch over the wall into the grounds of the estate. There were two sharp barks, followed by a series of snuffling noises, then the sound of the dogs running. After that all was quiet.

Tracy turned to her confederate. "Let's go."

The man, Jean Louis, nodded. She had found him in Antibes. He was a thief who had spent most of his life in prison. Jean Louis was not bright, but he was a genius with locks and alarms, perfect for this job.

Tracy stepped from the roof of the van onto the top of the wall. She unrolled a scaling ladder and hooked it to the edge of the wall. They both moved down it onto the grass below. The estate appeared vastly different from the way it had looked the evening before, when it was brightly lit and crowded with laughing guests. Now, everything was dark and bleak.

Jean Louis trailed behind Tracy, keeping a fearful watch for the Dobermans.

The ch��teau was covered with centuries-old ivy clinging to the wall up to the rooftop. Tracy had casually tested the ivy the evening before. Now, as she put her weight on a vine, it held. She began to climb, scanning the grounds below. There was no sign of the dogs. l hope they stay busy for a long time, she prayed.

When Tracy reached the roof, she signaled to Jean Louis and waited until he climbed up beside her. From the pinpoint light Tracy switched on, they saw a glass skylight, securely locked from below. As Tracy watched, Jean Louis reached into the rucksack on his back and pulled out a small glass cutter. It took him less than a minute to remove the glass.

Tracy glanced down and saw that their way was blocked by a spiderweb of alarm wires. "Can you handle that, Jean?" she whispered.

"Je peux faire ��a. No problem." He reached into his pack and pulled out a foot-long wire with an alligator clamp on each end. Moving slowly, he traced the beginning of the alarm wire, stripped it, and connected the alligator clamp to the end of the alarm. He pulled out a pair of pliers and carefully cut the wire. Tracy tensed herself, waiting for the sound of the alarm, but all was quiet. Jean Louis looked up and grinned. "Voil��. Fini."

Wrong, Tracy thought. This is just the beginning.

They used a second scaling ladder to climb down through the skylight. So far so good. They had made it safely into the attic. But when Tracy thought of what lay ahead, her heart began to pound.

She pulled out two pairs of red-lens goggles and handed one of them to Jean Louis. "Put these on."

She had figured out a way to distract the Doberman, but the infrared-ray alarms had proved to be a more difficult problem to solve. Jeff had been correct: The house was crisscrossed with invisible beams. Tracy took several long, deep breaths. Center your energy, your chi. Relax. She forced her mind into a crystal clarity: When a person moves into a beam, nothing happens, but the instant the person moves out of the beam, the sensor detects the difference in temperature and the alarm is set off. It has been set to go off before the burglar opens the safe, leaving him no time to do anything before the police arrive.

And there, Tracy had decided, was the weakness in the system. She had needed to devise a way to keep the alarm silent until after the safe was opened. At 6:30 in the morning she had found the solution. The burglary was possible, and Tracy had felt that familiar feeling of excitement begin to build within her.

Now, she slipped the infrared goggles on, and instantly everything in the room took on an eerie red glow. In front of the attic door Tracy saw a beam of light that would have been invisible without the glasses.

"Slip under it," she warned Jean Louis. "Careful."

They crawled under the beam and found themselves in a dark hallway leading to Count de Matigny's bedroom. Tracy flicked on the flashlight and led the way. Through the infrared goggles, Tracy saw another light beam, this one low across the threshold of the bedroom door. Gingerly, she jumped over it. Jean Louis was right behind her.

Tracy played her flashlight around the walls, and there were the paintings, impressive, awesome.

Promise to bring me the Leonardo, Gunther had said. And of course the jewelry.

Tracy took down the picture, turned it over, and laid it on the floor. She carefully removed it from its frame, rolled up the vellum, and stored it in her shoulder bag. All that remained now was to get into the safe, which stood in a curtained alcove at the far end of the bedroom.

Tracy opened the curtains. Four infrared lights transversed the alcove, from the floor to the ceiling, crisscrossing one another. It was impossible to reach the safe without breaking one of the beams.

Jean Louis stared at the beams with dismay. "Bon Dieu de merde! We can't get through those. They're too low to crawl under and too high to jump over."

"I want you to do just as I tell you," Tracy said. She stepped in back of him and put her arms tightly around his waist. "Now, walk with me. Left foot first."

Together, they took a step toward the beams, then another.

Jean Louis breathed, "Alors! We're going into them!"

"Right."

They moved directly into the center of the beams, where they converged, and Tracy stopped.

"Now, listen carefully," she said. "I want you to walk over to the safe."

"But the beams  - "

"Don't worry. It will be all right." She fervently hoped she was right.

Hesitantly, Jean Louis stepped out of the infrared beams. All was quiet. He looked back at Tracy with large, frightened eyes. She was standing in the middle of the beams, her body heat keeping the sensors from sounding the alarm. Jean Louis hurried over to the safe. Tracy stood stock-still, aware that the instant she moved, the alarm would sound.

Out of the corner of one eye, Tracy could see Jean Louis as he removed some tools from his pack and began to work on the dial of the safe. Tracy stood motionless, taking slow, deep breaths. Time stopped. Jean Louis seemed to be taking forever. The calf of Tracy's right leg began to ache, then went into spasm. Tracy gritted her teeth. She dared not move.

"How long?" she whispered.

"Ten, fifteen minutes."

It seemed to Tracy she had been standing there a lifetime. The leg muscles in her left leg were beginning to cramp. She felt like screaming from the pain. She was pinned in the beams, frozen. She heard a click. The safe was open.

"Magnifique! C'est la banque! Do you wish everything?" Jean Louis asked.

"No papers. Only the jewels. Whatever cash is there is yours."

"Merci."

Tracy heard Jean Louis riffling through the safe, and a few moments later he was walking toward her.

"Formidable!" he said. "But how do we get out of here without breaking the beam?"

"We don't," Tracy informed him.

He stared at her. "What?"

"Stand in front of me."

"But  - "

"Do as I say."

Panicky, Jean Louis stepped into the beam.

Tracy held her breath. Nothing happened. "All right. Now, very slowly, we're going to back out of the room."

"And then?" Jean Louis's eyes looked enormous behind the goggles.

"Then, my friend, we run for it."

Inch by inch, they backed through the beams toward the curtains, where the beams began. When they reached them, Tracy took a deep breath. "Right. When I say now, we go out the same way we came in."

Jean Louis swallowed and nodded. Tracy could feel his small body tremble.

"Now!"

Tracy spun around and raced toward the door, Jean Louis after her. The instant they stepped out of the beams, the alarm sounded. The noise was deafening, shattering.

Tracy streaked to the attic and scurried up the hook ladder, Jean Louis close behind. They raced across the roof and clambered down the ivy, and the two of them sped across the grounds toward the wall where the second ladder was waiting. Moments later they reached the roof of the van and scurried down. Tracy leapt into the driver's seat, Jean Louis at her side.

As the van raced down the side road, Tracy saw a dark sedan parked under a grove of trees. For an instant the headlights of the van lit the interior of the car. Behind the wheel sat Jeff Stevens. At his side was a large Doberman. Tracy laughed aloud and blew a kiss to Jeff as the van sped away.

From the distance came the wail of approaching police sirens.