'Why will this Change be dangerous for you?'

'I become larger. The stitches will tear open. If this begins to happen you must. . . kill me. I will no longer be Ustarte. And what I become will . . . slaughter you in its agony. You understand?'

'Yes. Rest now.'

For a human it would have been sound advice, but Ustarte knew that if she did not stay conscious the swirling would begin again and she would metamorphose. She lay very still. Her thoughts began to drift. Several times she almost lost the focus. She saw again the breeding pens, felt again the terrible fear she had known. The crippled girl, dragged from her home and brought underground to the ceaseless horror of the pens. Sharp knives cutting into her flesh, noxious liquids being forced down her throat. Each time she vomited more of the fluid was poured into her mouth. Spells were cast, sharper than knives, hotter than fire, colder than ice.

Then the awful day when her frail body was merged with the beast. Its terror and rage swamped her, as its molecules flowed within her human frame. The pain was indescribable, every muscle swelling and cramping. The child was swept away in a sea of blackness. But she had clung on to her individuality, despite the roaring of the beast in her mind. Sensing her presence, the beast had calmed.

Strange dreams followed. She felt herself running on all fours, her great limbs powering her across the plain at terrible speed. Then the leap to the back of the deer, her fangs closing on its neck, dragging it down, warm blood filling her mouth. She almost lost herself in the blood-memory – but she clutched the tiny spark that was Ustarte.

She remembered the day she became aware of voices. 'This new Kraloth does not conform, Lord. It sleeps twenty hours, and when awake seems confused. We have noted tremors in the muscles of its hind legs, and occasional spasms.'

'Kill it,' came a second voice, harsh and cold.

'Aye, Lord.'

The thought of dying flooded Ustarte with a burst of energy, and her spirit flowed up from the dark recesses of the bestial body. She felt again the pull of the flesh, the power of the muscles in her four limbs. Her eyes opened. She reared up, trying to speak. A low, guttural growl rippled from her throat. Her paws struck at the iron bars of the cage. A man in a green tunic pushed a long stick through the bars. Something sharp and bright upon the end of it stabbed into her flesh. Fire flowed into her flanks.

Instinctively she knew it was poison. How she dealt with it remained a mystery to her to this day. She could only assume that the merging had created in her an unforeseen talent, enhancing her lymphatic pathways in such a way that she could draw the poison into her system, breaking it down into component parts and subtly changing it.

She had dropped to her haunches, waiting silently until the poison was dispersed harmlessly. Now she became aware of the thoughts of the three men in the room. One was waiting to go home to his family. Another was thinking of a missed meal. The third was considering murder.

Even as she linked to the thought she felt the man close his mind to her. A golden spell lanced through the bars, flowing over her body with whips of fire. She writhed under this new pain.

So desperate was she to escape it that she fled deep within the bestial body, allowing the beast control. It raged around the cage, slashing its great paws at the bars, bending them. Still the pain increased. Ustarte tried to flee again, surging up through the body, as if trying to claw her way free of the tortured flesh.

And in that moment she found the key that would save her life.

The beast withdrew. The spirit of Ustarte swelled. The body fell to the floor of the cage, writhing and Changing.

When she awoke she was resting in a bed. Her body was no longer quite that of the beast, but neither was it human. Her shoulders and torso were covered in thick, striped fur, her fingers were tipped with retractable talons. 'You are a mystery to me, child,' said a voice. Turning her head, she saw the third man sitting beside the bed. He was wonderfully handsome, his hair golden, his eyes a summer blue. The eyes of a kindly uncle, she thought. Yet there was no kindness in him. 'But we will learn to solve it.'

Two days later she had been taken to a stockaded palace-prison high in the mountains. Here there were other mutations, man-beasts and were-creatures, the subjects of failed experiments. There was a serpent with the face of a child. It was kept in a domed cage of thin wire mesh, and fed on live rats. The creature did not speak, but at night it would make music, high and keening. The sound would tear at Ustarte's soul every night for the five years she was imprisoned in that, awful place.

Unspeakable acts were committed against her body, and she in turn was trained to kill and feed. For two years she refused to kill a human. For two years Deresh Karany, the golden-haired sorcerer, subjected her to dreadful pain. Ultimately the torture broke her resistance, and she learnt to obey. Her first kill had been a young woman, her next a powerful man with only one arm. After that she learnt not to remember the faces and forms of her victims. Time and again Deresh Karany would force her to Change, and once in the bestial form she would be directed against some hapless human. Her long fangs and terrible talons would rip into the frail flesh, tearing off limbs, lapping up blood and crunching brittle bones.

She was a good Kraloth, obedient and trustworthy. Not once – in either of her forms – did she turn on her jailers. Not even a growl. Her obedience was instantaneous. And day by day they grew more complacent about her. They thought they had her beaten. She could read it in their thoughts. Never, since that first day back in the city, had she let them know of her other powers. She was careful not to betray her talent. Ustarte knew that Deresh Karany sensed them. Once he had walked towards her with a dagger in his hand. His thoughts were clear. I am going to ram this blade into your throat.

'Good morning, my lord,' she said.

'Good morning, Ustarte.' He sat beside her. 'I am very pleased with you.'

I am going to kill you!

'Thank you, my lord. What do you require of me?'

He had smiled and sheathed the dagger. 'The creatures in this place are unique; twin forming is so rare. How does it feel when you shift from one form to the other?'

'It is painful, Lord.'

'Which form gives you the most pleasure?'

'Neither gives me pleasure, Lord. In this, my near-human form, I derive some satisfaction from study, from the beauty of the sky. In Kraloth guise I glory in power and strength and the taste of flesh.'

'Yes,' he said, nodding, 'the beast has no perception of abstracts. How then do you control it?'

'I cannot fully control it, Lord. It is wild and savage. It obeys me because it knows I can deny it existence, but it constantly seeks ways to overcome me.'

'The spirit of the tiger remains alive?'

'I believe so.'

'Interesting.' He fell silent and seemed lost in thought. Then he met her gaze. 'Back in the city I sensed you reaching out and touching my mind. You recall this?'

She had waited for this moment, and knew it would be dangerous to offer a complete lie. 'Yes, Lord. It was most mysterious. It was like flowing up from a deep sleep. Suddenly I heard distant voices, though I knew they were not real sounds.'

'And this has not happened since?'

'No, Lord.'

'Let me know if it does.'

'I will, Lord.'

'You are doing well, Ustarte. We are all proud of you.'

'Thank you, Lord. That is most pleasing to me.'

One day, as she strolled in semi-human form, she saw that the small postern gate was unlocked. She stood in the doorway gazing out upon the mountain path leading to the forest. Reaching out with her mind, she sensed the watchers close by, reading their thoughts. The door had been left open for her. Concentrating, she pushed her talent further. Five more guards were hidden behind the rocks some fifty paces from the postern gate. They were armed with spears and two held a strong net.