Cassie had no idea how it had happened. One minute, she was soaking in a bubble-filled bathtub, nearly asleep, and then she was standing in an open room, dressed in a sleeveless black minidress, with bare legs, and wearing and high-heeled shoes. She had no idea how much time had passed. She had no idea how much had happened to her in that intervening time. She would be amazed when she found out exactly what that had happened.

She never really heard the words, but they popped into her mind and she somehow knew that they were meant for her. How do you feel?

Cassie frowned and wondered silently who was speaking to her. Thinking at you. Not speaking.

"What?" Cassie was so stunned at the thought that she spoke aloud, in spite of herself.

How do you feel?

Cassie thought about the question and realized that she felt better than she ever had in her life.

That is good. You had three forms of cancer. They have been cured.

"How can that be? I've always been as healthy as a horse!"

You also had the beginning of a heart condition, the early stages of diabetes, and the initial onset of macular degeneration. Those have been cured as well. Your mind is having difficulty believing that all this repair has transpired. Please look at your left arm.

Cassie obeyed and was astonished to see that the scar from a terrible childhood cut was gone. Slowly, she lowered her arm and took stock of herself once more. She realized that she really did feel better, healthier than she ever had. She wondered if she looked differently and, at the thought, an image of herself appeared before her. Past the point of wondering how such things were happening with her mere thoughts, she resigned herself to the existence of unsolvable mysteries and stared at herself. The black hair looked more lustrous than it ever had did. The blue eyes were sharp. The strong, beautiful features, the high cheekbones, showed a new, healthier tone. She flexed her arm, noticing the bicep that sprang up, looking at the strong shoulders. At her thought, the image before her turned and flexed her calves, then turned back around, pulling the short skirt up slightly higher and flexed the quadriceps. Overall, she had the appearance of a fitness competitor, an appearance she had worked very hard to achieve, very hard to maintain.

No changes were made to your muscles, or to their strength. But all your illnesses have been cured. You have been given immunity to every disease. Only a massive injury can do lasting damage to your body, such as falling from a great height or having a limb or digit severed. Lesser injuries will heal themselves without the involvement of physicians.

What's the catch? Cassie thought. Nothing comes for free. He must want something from me.

Only that you do that which you enjoy. You enjoy the feel of the strength of another woman in contest with your own. The longer and more difficult the contest, the more you enjoy it. What is asked of you is that you do this, where the risk and the reward are greater than you could ever image. That, too, should heighten the excitement for you. The fate of Earth will be in your hands.

My hands? Cassie was astonished by the enormity of what was being suggested. In her mind were images of strangely helmeted soldiers marching people into camps, killing people by the thousands. Cities were being bombed. These images swam through her mind within a microsecond. They were equipped with weapons and armor the like of which she had never imagined. And, deep inside, she knew that what was she was seeing was true. That it could really happen. She wanted more than anything to defend her planet, but how? How would it work?

Another world has petitioned for the right to conquer Earth. Several centuries ago, they lost a war against another race. As part of their armistice, they are required to petition and receive permission before waging any war against any other world. They now petition to declare war on Earth. Earth has no chance of defending itself. They have technology far superior to anything that Earth could develop in time. The other world was offered a chance for acceptance of their petition, which would be based on whether your world was strong or weak.

Your world and theirs was seeded from a common race, millennia ago. Your development is parallel. They resemble you, physically. Each world has strong men, men who would love to come and prove themselves for the glory of their world. But the true life of your race, like theirs, comes from woman. You are the mother of your world. You will feel what is at stake, for the children you do not have. But you can empathize with those who do have children, who would be taken into slavery by your oppressors. Most men do not share that trait.

A woman of that planet has been selected. She is identical to you in height and build. In fact, all of her dimensions are identical to yours. She, too, loves the feel of a test of strength against an equal as much as you do. Each year, you will both be transported to a place where you will meet in two tests of strength. When one of you has defeated the other in both tests, that woman's planet will suffer the loss. Two days before the contest, you will receive a mental image of what the contest will be. In this way, you will each know what the contest rules are before you engage each other. The length of the contest between you is thirty years. If, at the end of that time, neither woman has won for her planet, you will both be retired and two new women selected.

It will be primal, purely muscular, between you. Your body, your strength, against her body, her strength. This is a duel between you and she, make no mistake about that. Your planetary survival is at stake. Both of your cultures have rituals associated with dueling. Each of you feels arousal at the thought of a contest with an equal, so your rituals may take whatever forms you both choose. She has no spoken language. Her people communicate through telepathy. However, there is a strong commitment to privacy among her people. Thoughts must be deliberately broadcast at the recipient. Your species is not yet equipped for such communication, though there will be a certain empathic connection between two women so remarkably alike.

The two contests will be selected from your memories and imagination. One will be selected from her culture, and one from yours. Many of these contests will appear similar in nature to you both.

Only one question remains. Will you accept your role?

Cassie felt her nipples hardening with excitement at the thought of the duel with the other woman. Part of her was terrified at the thought of what would happen if she lost, but the one overwhelming emotion she received from these thought transmissions was unyielding fairness. She had as good a chance to win two contests as her rival. For a brief moment, she wondered what would happen if she declined.

Earth loses by default.

That takes care of that. "I accept."

You will now meet your opponent. There will be no physical contest between you at this time. You will be brought together again in one Earth year, when you will begin your duel.

There was a sudden shimmering to her left, and Cassie turned to look at the most beautiful woman she had ever seen. She was a mirror image of Cassie in height and build, with long dark brown hair and the almond eyes and skin of a Polynesian. She was wearing a gray baggy sweat-suit type affair, with black high-heeled shoes.

As the woman looked at her, she seemed to shimmer again and Cassie, for a moment, thought that she saw a perfect nude body, briefly wondering if she, too, was now that perfect. When the shimmering stopped, the other woman was dressed identically to Cassie.

Each of you appeared before the other dressed in the clothing you each believed was perfect for such a duel, because of the effect you wished to cause in the other. When she saw you, Cassie, she believed that your clothing was more appropriate, and it was changed.

It was having an effect on Cassie, all right. She was frighteningly eager to match any part of her body against that of the other beauty. Her breasts swelled and her nipples hardened, jutting out through the material of the dress for the entire world to see.

Amazingly, her rival was showing an identical effect. Cassie's eyes were riveted on the other woman's breasts, which jutted out in a match of her own. She could feel the brown eyes of the other woman on her legs and she flexed her calves and quads, as the other woman did the same. Slowly the gazes worked up, to the thighs held by the tight hems of their dresses, to the flat, strong stomachs, which promised to be a perfect match when that time came. They studied each other's bare arms, reveling in the muscle that the other possessed. The wide shoulders, the muscle hidden both by pose and clothing. Once more their gazes fell on the still-swelling breasts of the other, lingering for a moment at the hardened nipples. Each of them could have been looking into a mirror to this point.

The gazes continued up the neck, to the beauty of the other's facial features, and then, for the first time, their eyes really met. The other girl's lips parted when she saw the sultry stare of her new rival. Cassie's reaction was the same. Each challenged the other with her eyes to come closer, to meet her body to body.

Slowly, hips swaying gently, they crossed the distance toward each other, eyes locked, until they were about two feet apart. Each woman stopped as though it had been scripted. For a long moment, they simply gazed into each other's eyes, then each turned slightly to her right and they circled each other, once, then twice. Squaring up again, they closed those last six inches between them and their nipples made contact through the material of the dresses.

The effect was electric, each woman gasping and moving back a half step, catching herself with her muscled right leg. Eyes locked again and suddenly they could each see it in the other - the enormity of what they were there to do. Once more, the nipples touched, with the same gasp from each, but this time they did not move apart. The contact became painful, but neither moved away. Breathing became ragged as they faced each other, suddenly locked in a relationship of erotic, respectful hatred.

With a mind of their own, each woman's hands rose slowly, each knowing that if she did not test the strength of the other soon, she would surely die. The hands closed together, each woman ready to interlace her fingers with those of the other, as slowly and erotically as was possible. Cassie could feel the heat of her rival's hands, feel the stiff nipples challenging, beckoning the duel to begin-

She was in a bubble bath. With incredibly sore nipples.

For a moment, she wondered if the entire thing had been a dream. She lifted her left arm. The scar was still gone. She smiled and shook her head. As she released the drain, allowing the bath water to run out, she wondered what her new rival's name was.

Piri.

It had been a month since she had been approached by the Entity, as she had come to call the person or persons who had taken her that night. In that time, she had won a twenty million-dollar lottery. Apparently, the Entity had not wanted her to be distracted.

But she had been unable to get Piri out of her mind. She knew that any other experience she would ever have on Earth could never equal the intensity of a mere thumb-wrestling match with the alien girl. And that thought was driving her crazy-

Another month passed, and winter settled into Chicagoland. Cassie wondered if she was crazy, doing what she was doing now. But she was going to go off the deep end if she didn't do something. She had purchased a small warehouse and had converted the space into two rooms and a garage. One room was essentially an entryway or foyer. She had laid down carpet and arranged for good environmental controls in both rooms so that this facility could be used year-round.

She was dressed in a black business-type suit, with a very short skirt and buttoned matching blazer, with a sleeveless silk blouse underneath, bare legs, and black high-heels. She was - not warm - but not as cold as she could be. The temperature outside the building was minus ten degrees. She would be pretty warm soon, though.

In the center of the large room was a circle of light, perhaps twenty-five feet in diameter. Outside of the circle was near pitch-darkness. Cassie stood just outside of the circle, on the opposite side of the room from the door. She heard the door as it opened and closed.

She could see the outline of the other woman approaching the edge of the lighted circle, stopping on just the other side. There was the outline of a strong pair of high-heeled legs, with a skirt high up on the thigh. The similarity between the legs she now watched and she struck Cassie own. One leg entered the circle. She placed her own leg in simultaneously. The high heel shoe was green. The shape of the leg, including the calf and thigh muscles, was identical to her own. The hem of the skirt and maybe six inches above it was clearly visible, a dark green.

With the next step, she could see the other woman clearly. The woman was Cassie's exact height and build, with shoulder-length red hair and green eyes. She was wearing a dark green suit - short, short skirt and a closed blazer, which showed the top of a silk blouse underneath. The clothing style was identical to her own.

For a long moment, the two beautiful women regarded each other across the circle. Neither woman spoke.

Neither woman knew the other. They belonged to two different athletic clubs in Chicago, where such things as this could be networked. Electronic mail had been sent back and forth between the two clubs and discreet staff members at the clubs had worked out this meeting to the last detail. Negotiations had been conducted, with Cassie laying down the initial terms and the basic dress. The other had wanted some modifications to the dress, but the basic terms were agreeable to each.

Cassie felt her breath coming quickly and shortly as she looked at the incredible beauty of the redhead, though it was not with the same intensity as when she met Piri. But the thought of being locked in a test of strength with the redhead excited her. Especially if the other was as strong as she looked.

Each woman took one step further into the circle and slowly unbuttoned her blazer, eyes locked. With equal slowness, the blazers disappeared, tossed back into the darkness. Finally, their gazes dropped from the eyes to the body of the other. Neither was disappointed with what she saw. Inch by inch, they looked up from legs to the stomachs, where the blouse was drawn tightly into the skirt.

The blouses were nearly transparent, and each could see the breasts of the other clearly through the fabric, the nipples distended with excitement at what was transpiring between them. After a long moment, while they watched each other's breasts swell even more, their gazes shifted to the arms of the other, where they could see the tightened muscle, equal and identical.

Their eyes locked, the redhead's hazel eyes steady on Cassie's blue eyes as they approached each other, hips swaying gently as they walked, stopping with their breasts just inches apart. The lighting changed slowly, the bright circle giving way to more normal lighting, revealing the beautiful features of the two women more clearly, as each turned slightly to her right and began to circle the other. The diameter of their circle began to close with the second pass. They had circled five times and their left shoulders were almost touching when they stopped, turned and faced each other once more. Their nipples brushed through the silk fabric of their blouses and each woman gasped. The hardened nipples continued to press, dueling as the breasts swelled and each woman resisted the impulse to take a deep breath. In fact, the breathing of the women was incredibly shallow, maintaining the contact of their nipples, and only their nipples. Each woman moved her own nipples slowly against that of her rival, allowing friction, and the continued swelling and hardening, to do its damage. The movement was less than an inch for each of them, not enough to allow the other's nipples to ever escape the duel between them.

Eyes bored in against eyes, a test of wills as well as arousal occurring between the two beautiful women. As the pressure between them grew, and the friction of the fabric took its toll on this most sensitive area, the pain grew in their eyes. Still, neither woman moved to end this duel. After another minute, the pain had grown to the point that each woman had tears in her eyes. Still, neither moved away.

Time seemed to stand still. The only sounds that each woman could hear was her own breathing, the breathing of her rival, the grunts of pain that each began to emit, and the nearly silent rustle of silk against silk. A hatred grew between the two women as their long duel of wills and endurance continued - it became apparent in their eyes. A faint sheen of sweat, caused by pain and arousal, was evident on each woman.

After five minutes of agony, and almost as if a silent cue passed between them, the movement stopped and the two women stood still, tear-filled eyes still locked. A draw was declared, without a word being spoken. Neither could break the will nor pain threshold of the other. Oddly, each felt the nipples of the other harden even more as she realized that she may well be facing her equal.

Breasts compressed as each woman moved her right leg forward, the inside of their right thighs pressing together, as high as the tight, short skirts would allow. There was a gasp of arousal from each of them as the steely thigh muscles flexed against each other. Eyes still locked; each woman unbuttoned the top two buttons of her blouse and buttoned her own blouse to her rival's.

For a long moment the two beautiful women stood still, eyes locked, letting each muscle that was in contact flex as they dueled with their wills once more. They each hated the other, the desired result of their preliminaries in this meeting, and it was almost time for the main event. Each woman moved her left hand behind the other, placing her palm flat in the small of the other's back. Slowly, the right hands rose slightly over their heads and the palms pressed together. Each woman pressed until her arms trembled slightly, continued for about ten more seconds, then eased the pressure.

Sensually, the fingers of the right hands interlaced, while the pull from the hands on their backs increased. They strained against each other, slightly, as each pressed her fingers as far down into the web of the other's as she could, and there was strained breathing from each. Pelvises pressed together as the left hands pulled tighter, and each felt the rock-hard abdominal muscles of the other as their straining duel continued. Thighs quivered between arousal and effort as the strain continued there.

Slowly, the resistance in the hands overhead built up, while the hatred in their gaze built up to match. The skin around the red-painted fingernails turned white as they strained against each other with all their power. Neither woman could move the other, as the grunts became louder and stronger. Teeth were bared and sweat streamed down their faces, between their breasts, between their pressed thighs. Each could feel the heat from the other's pelvis, and their stomachs, pressed tightly together.

Vision blurred as the duel went on, partially because of the sweat running into their eyes, partially because their faces drew closer and closer together. Thighs quivered more, as their arousal level rose, and as the two slightly bent legs lost more and more power - power that was needed for the test of pure strength that went on overhead.

There had been a risk of orgasm in this duel - each of them knew it, and each knew that, if she was first, she would lose. The duel itself was one of pure strength, that was the agreement, but each was aroused by the strength of the other, which seemed a perfect match for her own. The preliminaries had been constructed between them to heighten the arousal between them and give each other a a measure of the sensuality each felt in her own strength. The positioning of their bodies was partially done to ensure the risk of orgasm. With their blouses buttoned together, neither woman could be forced very low if her strength did fail. With the thighs positioned as they were, any loss at all might mean an instant orgasm.

Cassie had never lost a test of strength to another woman. She would not have been surprised if she heard that her opponent had a similar record. Her own idea of the perfect duel was one that neither woman won or lost- a draw. She was searching for a rival who would stand up to the best that she had to offer, and to whom she could stand as well. When the duel of nipples between she and the redhead ended in a draw, her arousal level had shot through the roof.

Each could feel the breath of the other on her own lips, breath released by grunts that were slowly turning into sobs as neither woman could gain any headway and the pain in their right arms increased. Each woman cocked her head slightly to the right as their noses bumped together. Suddenly their mouths were a millimeter apart and each could feeel the heat of the other's breath trying to melt her light coat of lipstick. Each woman moaned in agony now, of two different kinds.

The bare legs were sweat-slicked and hot, worn out from supporting the partial weight of their owners on stilleto heels. The muscles were still hard, pressed tightly together, but the trembling increased as they matched each other longer and longer. Crushing pressure on the pelvic bones was causing an arousing effect as well. Overhead, the agonizing test of strength was a dead statemate. Each woman was in danger of an orgasm and, though they could not know it, this was dead even as well.

The two moaning mouths brushed lightly, then pressed together, then fused as each, recognizing the risk, began to try and excite the other into the first orgasm. Tongues thrashed thickly, wetly, around the moans from the duel of their muscles which continued unabated. Every part of their bodies burned, either from the effort of their strength, or their excitement.

Pelvises collided violently as the orgasm shook them both at the same time and each tried to keep her right hand straining, tried to be the one spent last. With a final sob, the redhead released her pressure, just mere seconds before Cassie would have had to do the same. Neither could release the other's hand and the bodies had no strength to separate - not even to end the kiss.

Finally, they separated, the kiss being the last thing to come apart, and the two beautiful women glared at each other with unabated hatred. Both women were soaking wet, as though the blouses they wore we as if non-existent. The skirts were wrinkled, the hair wet and flat, and the faced streaked with tears, makeup, and the color of two who had strained for hours.

Neither woman spoke. It was clear that neither wanted the duel to end, that both wanted a resurgence at another time. After a long minute of a battle of wills, the redhead turned and retrieved her blazer from the floor, turning and walking from the room, without a word.

Cassie stepped out of the shower and into a bathrobe. She walked out to the den of her new house and poured herself a glass of cabernet, then sat down on a fabric-covered recliner, putting her feet underneath her.

She felt strangely unfulfilled. She had enjoyed the duel with the redhead and felt the arousal even now. And she had a strange feeling that perhaps no other woman on Earth would present her with the same challenge that the redhead had.

No woman on Earth.

Perhaps that was the key. She would meet the redhead again, she was sure. Probably other women as well. But she knew against whom her ultimate battle would be achieved.

Piri-