He lies still, half in the shelter and half out. If he were human his legs would be burning in the sun. But he is not human. He has had ample proof of that over the last three, four, maybe five days.

He is spent. He is so tired that his chest barely moves as he breathes. His eyes are half closed and he is glad of the dark shade above him because if he could see the light he thinks his head would split apart.

Illogical. Of course his head would not suffer a physical failure on exposure to sunlight. But he doesn't have the resources to control the pain of headache that is snaking behind his eyes and through his temples.

The word logic settles in his mind like a cold compress on a wound. So peaceful and familiar a word. It is like a spar floating on the sea after a shipwreck, the only thing to which he can cling. Logic will support him and bring him to safety.

'Here. Drink this.'

Her voice is a momentary surprise. For a while he had forgotten that she was still there. But she is kneeling, he sees now, beside him in the sandy shelter, holding out a flask with an open top.

'For dehydration,' she says as he catches the odd chemical scent. 'You've lost a lot of vital minerals. You don't need to give me that look. My medical scanner tells me you have. It doesn't lie.'

He opens his eyes a little wider, letting himself focus on her appearance.

'I wasn't aware of giving you any look,' he says.

He sits up a little and drinks some of the liquid. It is salty and sharp and metallic and his mouth revolts at the taste. But he can also taste that is contains precisely the compounds that he needs. He drinks it and it settles in his stomach, heavy and cool.

'The hormonal imbalance is levelling out,' she says in a quiet voice.

She does not sound as if she is thinking of the days and hours of heat and lust, of his moving hands and his hungry lips. She does not seem to be thinking of lying out on the sand under the moonless sky, nerveless with exhaustion. She sounds as if she is standing in the sickbay aboard ship, reading the chart of an anonymous patient and proclaiming him well.

'Christine,' he says, but he doesn't know what words to use to follow that one.

He is grateful, yes. Grateful and exhausted and confused. He is so tired. He has barely eaten despite her exhortations. He must have lost something like twelve pounds of weight. His cheeks and chin are rough with the stubble of an unshaven beard. His hair is tangled and filthy and his skin is covered in dust. His spine is a disjointed line of beads discarded on the floor. His legs are the broken, senseless legs of a doll dropped by a child. He is so tired that he could fall into a grave and lie there without emotion as the earth was scooped in upon him. He would be grateful that he could rest, but nothing more.

'You don't have to say anything,' she says, breaking his silence.

She is not looking at him. Her eyes are red-rimmed and her hair loose and lank. Her clothing is dirty, her skin sunburnt to a rich brown. Her irides are blue and tired and focussed on the sand beside him. He sees her hands, still and loose at her sides. She looks as if she has let go of something precious and let it drift away on the tide.

'Christine,' he says again.

Logic tries to assert its dominance, but it is chased out by regret, love, pity, hopelessness. He doesn't know where to go from here. She is everything he could wish for, except Vulcan. She would accept him without question. She would stand beside him. She would understand. She is young enough still, and ripe and lean and tall. Her skin is firm and her hair is dark and her eyes are alive despite the exhaustion. She would wait for him to return from every duty mission and welcome him with upturned lips and open arms.

She would mourn for him if he were killed. She would sit beside his bed if he were injured beyond hope, and she would cry for him. If they served together their minds would always be twined, and when the ship was in danger he would be thinking of her, and when lives in sickbay were in danger she would be thinking of him. No man in love can work efficiently when the object of his desire is in danger.

There is no logic to a relationship on a starship. There is no way that it can work, no way that two people with their minds entwined can work safely. Neither is there logic to a relationship where the two halves are separated, where one is ever moving about the wandering stars and the other planet-bound or tied to another ship. There simply – is no logic.

He is glad he is not human, because he thinks that in his exhausted, worn-out, drained state that the sadness of that realisation would kill him.

He raises his hand to her and captures her fingers in his own. For once she feels warmer than he does.

'I cannot let this continue to happen,' he says quietly. 'I cannot use you like this.'

'You have never used me,' she says, and something in her voice sounds broken. 'Never.'

'There is only one logical course to take,' he says, his eyes focussed on the dark stone above him, neither seeing it nor blind to it. 'There is a place on Vulcan called Gol.'

'I know,' she says as if she is biting into a bitter pill. 'I know about Gol.'

'A master of the Kolinahr is not vulnerable to his – Time,' he says with difficulty. Even after all that has happened, still it is hard to voice it. Somehow intimacy upon intimacy does not compare to actually voice thoughts and feelings.

Her fingers are moving on his, soft and slow. He looks at her fingernails and sees that they are dirty and chipped. When they finally emerge out of the desert they will not look fit for civilisation.

In a very controlled voice, control almost worthy of a Vulcan, she says, 'You would not need to worry about your Time if you stayed with me.'

He swallows. His eyes close. He cannot look into her face. When he opens them he looks at the square of dazzling sunshine outside the shelter.

He gets to his feet and moves outside, and she follows him. He takes her to where the spring flows, where the trees grow rich and burdened with fruit and the heat of the sun is tempered by shade and a cooler breeze. He picks a fruit and gives it to her, and she holds it but does not lift it to her lips. She holds it like an infant, he thinks, like something that is so precious that she would never let it fall.

'Not everyone can achieve the Kolinahr,' he says in a slow voice. Their fingers are still tangled. He can feel her pulse through her fingertips. 'Not everyone has the discipline.'

'And if you can't?' she asks him. There is less control in her voice now. Something like a sob modifies her words.

He closes his eyes briefly, but keeps on walking under the trees, feeling the soft and shade-cooled sand moving between his toes, flattening against the soles of his feet. This, perhaps, is paradise, if paradise has ever existed. If there were a god for him to make bargains with, he would consider making one now. But there is no god. There is simply space, unending and unyielding, filled with countless miracles of science. There is simply that dark arch of sky and the stars within, and after some distance there are other planets with other beings looking up through the fragile bubble of atmosphere that holds them and constructing their own myths and questions about what may exist in the dark reaches of space.

'If I can't…' he echoes.

To follow the Kolinahr he will be required to give up those delicate, dangerous intricacies of space. To follow her he will be required to give up the same. But the Kolinahr, at least, will give him the resources to accept both losses. There is no regret in the mind of the Adept. There is only peace and acceptance.

'I love you,' she says in a choked voice. 'I have always loved you.'

He stops walking. The effects of his Time must still be running in his veins. His throat feels hard and he cannot swallow. There is moisture in his eyes.

He turns to her and cups her cheek in his hand. She raises her face to him and he leans closer. The air between their lips is like water, thick and warm and so hard to pass through. But he moves forward and his lips touch hers and his fingertips wipe tears from her cheek. She tastes of fruit and warmth. He would believe in God and sell his soul to be human at this moment. But he chose his path long ago. It is so hard to step from a paved way and strike out into the wilderness.

He doesn't know how long he has been standing here, his lips against hers, his tongue stroking the insides of her mouth and his hands trying to touch her entire body. He has fallen into an oblivion that is softer and kinder than orgasm. He feels her hair and the beating of her heart under the shell of her ribs. He feels her skin and the warmth of her blood and hears her breaths coming short and shallow near his ear.

He gently lowers her to the ground and he strokes her body with the flatness of his palms and his searching fingers and he feels her in a way he could not when his mind was inflamed with a hormonal desire. He nudges her legs apart and he touches her there and sinks himself into her, sinking his tongue into her mouth at the same time and feeling as if there are not two beings here, but one. This is it, he knows. This is the last time he will permit himself to feel in this way. This is the last time he will know such intimacy.

She is velvet and he is a sword slipping safely into its sheath. She is a harbour and he has come to rest. This moment is so, so right that he thinks that the Adepts at Gol must be madmen or freaks. That thought is so fleeting that it is tossed into the wind before he can think any further. He will not think of them. He will think of nothing but the feeling of her around him and her warm human presence, of the delicate touch of her mind and the knowledge that she accepts him as a flower accepts a bee. He closes his eyes and thinks that even if the universe continues through infinity, there will be no time for him apart from this present moment when all the worlds are perfect and all the stars are aligned.