She was woken the next morning with a polite knock on the door. She opened her eyes and stretched, feeling more refreshed than she had in a long time. The knock came again. She examined herself critically in the mirror, deciding she didn't care enough about what he thought of her to have a shower or change. She settled for dragging a comb through her hair, wiping the worst of the mascara from her cheeks. She answered the door.

He was already halfway down the corridor, leading her in silence to an unfamiliar part of the ship. He opened the door to a small room, dominated by a large table with a chair on either side, covered wall to wall with books. A cabinet held a selection of shiny metal objects of indeterminate purpose. He took a seat and smiled brightly at her until she did the same.

'Right then,' he said, 'I'll start by teaching you how to shield your thoughts. I'll show you what I'm doing and then you try. Close your eyes.'

She favoured him with a foul look before she did as she was asked.

'Now,' he said, 'I want you to imagine a picture of me in your mind and try to reach out towards it'.

Instinctively, she imagined a softer, familiar him, staring at her with warmth in his eyes and the beginnings of a smile, reaching out for her hand. Not the image she wanted, she decided, smashing it into pieces. She thought of the way he had looked at her yesterday, his eyes flat, expressionless, face solemn.

'Alright,' he said, his tone completely level, unaffected, 'now reach out towards the picture.' She groped for a few minutes in silence, sensing some sort of wall between her mind and the image she had created.

He explained, 'That's what you need to imagine, something to keep what you're thinking in and everyone else out. It's just control and focus. Now, try again and tell me what you see.'

Intrigued, she reached out towards the picture again and started as a different image jumped, fully formed into her mind. 'Um, apple,' she said. The image was replaced. 'Banana', again, 'cat, dog, elephant.' She realised what he was doing. Quicker than thought she was incandescent with rage. She popped open her eyes. 'I suppose you think that's funny,' she snapped, 'stop treating me like a child!'

He raised an eyebrow at her, 'Ever done this before?'

'Yes,' she hissed, shooting a jumble of impressions of the last time she had sensed his thoughts at him. Desire. Passion. Need.

He sounded amused, 'Touché.'

She glared at him. He smiled benignly.

'Let's see how easy it is for you then, shall we?' he said. With a mutinous look she closed her eyes, imagined a wall. 'No, useless,' he said instantly, 'I can see straight through. You're feeling angry — which, by the way, won't help, you have to control your emotions. You're wondering if you smell because you haven't had a shower. You're wondering whether you've dribbled down your top in your sleep — the answer's yes — you're imagining stabbing me with a very sharp knife — could be scissors actually.'

He was actually going to try for banter, she realised, glaring at him mutinously from underneath her hair. Reaching behind him he yanked out some sort of plastic sheet and put it on the table, 'Read that, do what it says, and I'll see you again, same time tomorrow.'

And he was gone. She was so annoyed at the casual manner with which he had breezed in and out of her mind that she nearly jumped up and down in her chair. Focus, she told herself, control - if he can do it, so can I, and she pulled the tablet towards her.

He waited outside the door until he was sure she had started and then wandered off down the corridor, feeling absurdly pleased. He could shrug off the distress that some of her thoughts had caused him in his pride at how quick she was. If she carried on at that pace she'd be ready to go in a couple of months. His smile died. He wandered on.

Many hours later, her mind hurting and eyes aching, she decided she had had enough. She wondered if she should tell him she had finished. Tentatively, she reached out a hand to the TARDIS wall and imagined the blue box in her mind, silently asking where he was. Instantly, she saw a picture of him lying on the floor, underneath the console, wires and tools strewn everywhere, clearly in for the long haul. Seeing him, her ire raised and she decided that she didn't need his permission after all. Rising from the chair she stretched, feeling stiff and walked out of the room. She spent the next couple of hours pounding out her rage and frustration in running before she returned to her room, eating alone, sleeping alone, talking to no one.

When she arrived at the schoolroom the next morning he was already there, waiting for her, looking bored. 'Ready?' he asked — straight to business.

She tried to follow the instructions she had studied so carefully but he was too much for her. 'You're wondering what I had for dinner — nothing, not hungry. You're thinking about going running later, you're wondering if there's a pool — out the door, turn left, third on the right.' He opened his eyes, 'Alright, enough. Same time tomorrow?' And he was gone.

On the third day he retrieved one of the bits of the equipment from the cabinet, pushed some buttons on it, and told her to practice. It spent the whole day firing some sort of electrical signal at her and beeping until she threw it against the wall.

On the fourth day she decided to be late, swanning into the room an hour after her time, only to find him reading, completely unperturbed.

On the fifth day she decided not to turn up at all and spent three hours pacing her room, checking his whereabouts through the TARDIS wall every ten minutes. When she could stand it no longer she shuffled off to the schoolroom, to be greeted with a cheery grin and absolutely no recrimination whatsoever.

By the end of the second week they had reached an uneasy truce. She would see him for five minutes a day, during which time he would laugh at her efforts, giving her no encouragement or telling her what she was doing wrong, always smiling, bothered by nothing she did. She imagined beating his head in very slowly, with a spoon.

For his part, he lived for the short moments alone with her, killing the time until he could see her again with urgent missions, life and death escapades, the more difficult and dangerous the better. He was trying to hurt her and the only way he knew to make himself feel better was to punish himself in return. It was a half life, out in the universe on his own again, but knowing she was still waiting for him. By day, he took care to annoy her as much as possible and by night, he eased her dreams.

At the end of the third week she thought she would go mad if she didn't talk to someone else. She had learnt to check his location with a flick of her mind and when she sidled into the console room she already knew he wouldn't be there. She walked straight to the doors and found them shut against her. She couldn't get out. She kicked the door, and, for good measure, walked over to kick the console. She wished she could see outside and noted that the viewscreen had changed to show a dark, indistinct scene, too small to pick out the details. Deliberately, she imagined a large, wall mounted screen and heard a high pitched buzz as the walls rearranged themselves to provide one.

Outside was a place of metal, struts and braces making square patterns in the sky. The doubleness of her vision hit her with a vengeance as she looked at it, seeing the reflections of the structures until her mind was full of edges. She didn't fall. She forced herself to concentrate on different parts of the picture, the indistinct humanoid figures she could see moving. One was running towards the screen. She knew that run. She focused on the figure, drawing an imaginary circle around it, and saw the rest of the picture ripple and clarify into a single steady image. She could see that the running man was being pursued, other figures close behind and shards of red light flying past him at regular intervals. She could see his coat flapping as he ran, his arm held awkwardly, the rictus grin and feral glint in his eye.

As she stared, her vision split — one of the spooling images showing the red light hit him, the figures swarming towards him as he fell; in the other, the light missed and he ran on. She concentrated all her attention on the second image, reaching out to pull it towards her, slapping the other one aside, pushing it down. The light missed him and she heard the door slam open behind her. She turned. He was obviously injured. There was a cut below his right cheekbone and he was cradling one arm with the other. She took a step towards him, silently sending him a wave of concern. He flicked his good hand at her, waving her away.

The level of her background rage - always seething under the surface — rose: 'Where the hell have you been?' He rolled his eyes at her, taking something small and shiny from his pocket and putting it on the table. 'And that is?' she snapped.

He shrugged, 'Dunno, probably junk. You want to see where they were keeping it though'. He straightened, 'So, I assume because you're here that you're wanting another test?'

Her fingertips itched with violence. Not only had he locked her in, he'd put himself in danger, got himself hurt without her, had risked himself for something worthless and left her helpless to save him. And then brushed her off. Again. Her anger consumed her. If he wanted to play, she was ready. She fixed her gaze on his, filled her mind with the only images she thought would embarrass him, might provoke a reaction. Herself, spread beneath him, head thrown back, face suffused with ecstasy. Above, he moved slowly inside her, the corded muscles of his neck standing out as he strained towards release. Part fantasy, part memory, all weapon.

She could see she had hit him — his eyes widened slightly, then narrowed. In response, he fired back a stream of images — her body convulsing as she was shot by a Dalek, her eyes open in death in the ruins of an exploded building, her face contorted in pain as an alien claw sliced through her. Pictures of her death surrounded her at every turn, the direct consequence of the pictures she had shown him. Her chin came up. She accepted them all, did not flinch. She was human, her death was inevitable, and she had long ago understood the risks she ran. He couldn't intimidate her.

A thought occurred to him and he changed the thrust of his bombardment. Instead, he sent her images of him — chained, tortured, bloodied, surrounded by foes, dead and forgotten on the floor of some far away corridor, disintegrating into atoms piece by piece. He heard her gasp, and at long last, felt her slam up a barrier against him, closing her off from the stream of death and misery. He felt like dancing. Walking past her, he tousled her hair, murmured 'Good girl,' against her ear as he headed off to the medical centre to fix his broken arm. She might be angry, and brave, and quite happy to fight him, but despite all he had done, it was the thought of losing him that disturbed her most. He knew he should be disappointed but for the moment, just couldn't bring himself to it.

The next morning, he brought her a bird. He had thought hard about this move, knowing it would upset her, unable to think of any other way to tell her what she needed to know. She had to understand the consequences of her actions. Like the fact that the consequence of loving him was death, for example. There was a cause and effect she clearly hadn't grasped. Despite his lapse of the previous evening his decision was unchanged. Kill her love before it killed her and take her home. It made the bird necessary. He put the cage down on the table between them, removed the cover.

She looked tired again, he thought, a whisper of guilt ghosting through him for spending the night in the medical centre, instead of warding her. Fatigued or not, her defences were firmly in place now, and he had no sense of her thoughts, no insight into her soul. The desolate silence in his mind was a renewed sorrow, but he embraced it willingly, for her sake.

'Look at the bird, Rose', he asked in resignation, 'tell me what you see.'

She looked at the tiny ball of feathers, imprisoned in its cage. She knew how it felt. Another one of his pets, to be taken out and played with whenever he felt the need, patted on the head and told it was good and then put away again, forgotten. She felt she had lost who she was. Left alone for weeks on end, unable to leave but dreading to stay, helpless, useless, unimportant. She was a burden to him now, even her anger turned against her. She looked at the bird and saw herself.

She tried to bring the otherness of her vision into focus. As she stared at the cage she could see the short span of the bird's life moving in fast forward — egg to chick, chick to bird, bird to ashes. She didn't reply.

'Concentrate on slowing down the pictures,' he told her.

She tried, focusing on seeing an egg, and just an egg in the space where the bird had been. All her conscious thought she concentrated on one part of the image until she was aware that impression of feathers had been subsumed within a shiny shell. It was a tremendous effort though, she had no attention to spare for anything else as complex as moving, or thinking, or showing him what she saw.

She didn't need to show him. He could see for himself. Instead of a bird, the cage now contained an egg. She only retained an echo of the vortex, she had lost the power of life and death over the universe, but it seemed she wasn't entirely impotent either. What Rose saw was real. He raised his hands, massaged his temples. This wasn't going to be pretty.

She filled her mind with the egg and reached out towards feathers. She was rewarded with hatching, growing, struggling, flying as she pulled the next image and the next towards her. She was elated — she had mastered this so easily. As long as she focused hard enough, she could see anything she wanted. She wondered how fast she could go, tugging on the pictures like a rope, tumbling faster and faster. Abruptly there was a shake, and the ball of feathers in its cage stopped moving, falling on its back with a pantomime thud. She blinked, trying to open her eyes and realising they were already open. She saw him looking at her with concern.

She pushed her finger through the bars of the cage, poked the tiny form. 'What happened?' she asked.

'It's dead Rose,' he answered, 'you killed it.'

She laughed ' No,' letting out the word slowly as she breathed, still smiling.

He didn't see the joke. 'I've told you what you can see now,' he explained. 'Past, future, all of that. You can't just see it, you can change it too. Every time you reach out towards something, drag it closer, you make it happen. You've done it at least twice — you didn't know what you were describing when you woke up after Satellite 5 but you should have had some idea yesterday. It's not that I don't appreciate not being shot in the back, but the question is — what are you Rose? Twice, you've changed time to save me but you slaughtered nearly half a million Daleks to do it, and the bird is dead. What are you — saviour or destroyer? 'Coward or killer'?' he shrugged. 'Who are you to decide who must die and who can live?'

Choice. It was all about choice, she realised. He'd shouted at her about it from the time she woke up. She had killed. Easily, without conscience, taking away the choices of her victims. She didn't recognise herself anymore. She knew why he didn't love her, wanted her to leave, she was an abomination. She was empty, lost, riddled with guilt; unable to see how she could move forward, too afraid to confront what she had done. Once, she had asked him who he was. Now, she knew.

The next morning she beat him to the schoolroom, asked him to teach her in a distant, toneless voice he didn't know, the dead expression in her eyes wrenching at his heart. His throat constricted momentarily at the sight of her, the cost of his success. She hadn't slept, despite his best efforts. It wasn't the Daleks she was mourning, but the capacity for death she had discovered within herself, the loss of her innocence.

Pushing buttons, he produced a viewscreen to replace the books and filled it with a sea of flowers. 'One at a time,' he instructed. He retrieved a piece of folded paper from his pocket, threw it on the table. 'That's how many I think will die,' he said, leaving her.

She barely heard him. She spent the next three days concentrating on a single flower at a time, focusing until she could see one image of it, holding it steady, stilling the chaos before she allowed her sight to move either way. Three days of moving by precarious millimetres, making sure she didn't damage, did no harm. Three days spent looking at a sea of red roses so closely she didn't notice them at all. When she looked at the paper there was nothing written on it.

She progressed to plants, trees, fish, animals, mountains, landscapes, starfields, empty cities, ruined and alone. Days spread into weeks, months. She withdrew into herself, spending all her time locked in a desperate struggle to control her capabilities. She barely ate, but at night she slept like the dead. Eventually, she couldn't remember a time before she had opened the vortex, opened her mind. She saw him occasionally, but he passed through her mind like footprints in the sand, washed away by the next thought. She had nothing left of herself to give him. Once, he sat with her in front of a village sequence, asked her to tell him about the tumbledown houses, see the time when their mossy stones had been full of light and life, love and happiness. It made her cry.

The next day, there were people in the picture on her wall. She went more slowly still. She taught herself to see without touching, to master the reflections, to find the eye of the storm, the heart of the vortex and bring peace to her sight.

He appeared at the door of her room one night, and it was a surprise to her to remember that she knew him. 'Tomorrow, I'll take you home,' he said.

The Postman's Daughter and The Car Crash Bride by Sally Anne Palmer are available now on Amazon.