There was a garden outside. In real life, Severus had planted a garden on the other side of the house, full of herbs with useful magical or medicinal properties. But this was a defiantly useless garden full of flowers. He looked to see whether his dream-self had planted lilies in memory of Lily Evans, but most of this garden was given over to red roses. Apart from these, there were purple-blue irises with a splash of egg-yolk yellow, deep crimson amaryllis, huge yellow sunflowers lifting their faces to the sun, tiny wild violets, and proudly defiant stinging-nettles standing as guards around the borders of the garden, threatening intruders. Severus generally allowed nettles to grow in his herb garden as long as they didn't take it over, partly because he liked making nettle wine, partly because nettles had useful medicinal powers, but mainly because he had a soft spot for them. They were tough and aggressive and didn't give up no matter how often gardeners tried to eradicate them.

He looked out beyond the new garden, across the island. It looked a beautifully warm, sunny day. 'It's a long time since I've been swimming, except in dreams,' he added.

'Or I,' said Anakin. 'Could you – take me with you?'

' Can you swim with those things?' Severus asked curiously. The metal limbs looked very high-tech, but they were still Muggle technology, nowhere near as adaptable as magical prostheses.

'No,' Anakin admitted. 'These are not waterproof. I will have to wait for real limb grafts before I can truly swim.'

'So what you really mean is that you want one of us to hold you up in shallow water while you kick your stumps against the waves?'

'I promise not to complain about sand being coarse and irritating and getting everywhere,' said Anakin, with as much of a smile as his scarred face would permit.

'I thought we were discussing things I might do on my day off, when I need a break from looking after you?'

'We could do this on a day that isn't your day off. It's not much fun being someone who needs this much looking after either,' grumbled Anakin, and for a moment, despite his physically looking no younger, Severus could picture him as the annoying teenager he must once have been.

'I suppose so,' he conceded. 'Konstantine and I could take turns for one of us to look after you while the other swims further out.' Remembering that Anakin came from a desert planet, he added, 'Who taught you to swim?'

'Padme. When I was nineteen.'

'Who's Padme?'

'My wife.'

Severus hadn't felt comfortable asking about this aspect of Anakin's life. The one time he had watched a Star Wars film as a young man, he had assumed that, presumably, Anakin must have got married at some stage. But, logically, the fact that he had fathered two children didn't prove that any woman had loved Anakin Skywalker or chosen to have sex with him, let alone marry him. Perhaps he was just fantasising…

'No, she actually was my wife,' said Anakin.

Severus caught sight of something in his room that certainly didn't exist there in real life. A mirror. To be precise, a tackily ostentatious mirror that reached from floor to ceiling, with a fussy gold frame ending in two clawed feet, and the familiar inscription: Erised stra ehru oy tube cafru oyt on wohsi.

If his subconscious had decided that he not only wanted to grow sunflowers and roses but also wished he was better-looking, this was going to be embarrassing enough to make him vomit, he thought. Never mind that nobody would need to know what he saw in the mirror, since to Anakin it would reflect only his own desires.

When he had last seen the Mirror of Erised, six years before his death, it had shown him arm in arm with Lily, the two of them gazing adoringly into each other's eyes. Boggarts appeared to him as Lily, too – not as werewolves, to his surprise – but the Boggarts showed her rejecting him, telling him she had always despised him since the day he had first spoken to her when they were nine years old.

But now, the mirror showed him with his arm around a woman who wasn't Lily, or Narcissa Malfoy (why did so many witches have flower names?), or any woman he had known in real life. She was as tall as he was, not particularly pretty, but she looked warm and kind and intelligent, and very happy to be with him.

He scowled at the mirror. His reflection grinned back at him, with teeth as yellow and crooked as his own. This version of him was an older man with grey hair, and was wearing not his customary black, but a comfy-looking robe striped in mulberry and sky blue. With the arm that wasn't cuddling his wife, he cradled a baby who was probably his grandchild. Two young men and a woman who all looked rather like Severus were standing beside him, and a young man and woman who looked like his wife were standing by her side. A wife, five children and a grandchild.

His reflection took his arm from around his wife to take something from his pocket and hold it out for him to see. It was a tiny stuffed toy in the form of a spaniel, white with fluffy chestnut-brown ears. He tried to tell himself that he was just entertaining the baby with it, but somehow, he knew that his mirror-self was soppy enough that he actually was an adult who had a favourite cuddly toy. He grimaced at the thought, and his reflection laughed good-naturedly at his reaction.

He turned away from the mirror, sat down on the bed with his back to his reflection, and buried his head in his hands. This dream had been going so well, while it showed him things that he actually could ask for, here on the Rock. But what was the good of wishing he could have survived long enough to find love and have a family? Why did the dream have to taunt him with what could never be?

He stood up, and walked around the bed to turn the mirror to the wall. Before he could get the people in the mirror out of sight, his reflection gestured to something propped against the wall in a corner. A guitar. Well – thank you, reflection, for trying to make amends after reminding me how much I've missed out on.

'Does this mirror show the lives we might have had, if we had made better choices?' asked Anakin.

'No, it doesn't,' retorted Snape. 'Couldn't you make anything of the inscription?'

'As it's not in Aurebesh, no.'

'It's a mirror that shows us what we most desire,' Severus explained. 'We had it in Hogwarts Castle a few years ago, because it was being used as a magical hiding-place, as the Headmaster had decided that a school was the best place to hide a magical artefact that Dark wizards would happily murder to own.'

'The mirror was so important that you had to hide it in the castle?'

'No, we had to hide something in the mirror which is none of your business and was destroyed years ago. Anyway, what did you see?'

'Not what I expected,' said Anakin. 'At least – I saw myself, with Padme still alive, and Luke, and…'

'Leia? Your daughter?'

'Yes. She and Luke looked about ten years old. I never even knew they existed, when they were children. But – they were not the only ones in the image. I saw Obi-Wan Kenobi with Satine Kryze, and Ahsoka with a male Togruta I have never met.'

'Who's Ahsoka?'

'My padawan – my apprentice when I was still a Jedi,' Anakin explained. 'She left the Jedi Order after being falsely accused of a crime. But – in this vision, none of us was wearing Jedi robes – and all of us were married couples, with children. I saw Obi-Wan and Satine with a daughter the same age as my – my twins, and Ahsoka and her husband with four little girls – one orange like Ahsoka, one purple like Ahsoka's husband, one red, and one blue. The oldest, the purple one, was practising lightsaber-duelling with Luke, and Obi-Wan's daughter was duelling with Leia.'

Snape huffed impatiently. What did it matter who was duelling with who?

'Do people – fall in love, in this place?' Anakin asked. 'Do they marry and have children?'

'I don't know about falling in love,' Snape admitted. 'Sex might happen.' Personally, he hadn't been interested in having sex with anyone he wasn't in love with. He supposed that Konstantine probably had some sort of sex life, but he didn't want to know the details, and, as long as it didn't involve coercion in either direction, it wasn't a problem. 'But the only couples I know here are visitors who are couples in their own world and are either immortal, like Hephaestus and Charis, or still alive, like Nutt and Glenda,' he went on, hastily trying to clear his mind. 'Having children doesn't happen here, because nobody ages, so the process of conceiving, gestating and giving birth to a child, and seeing them grow up, cannot happen.' Though sometimes people who had reached adulthood in their own timeline regressed to childhood here, as he had regressed to kittenhood. 'This is a place between the worlds, where no stories happen, where we come to recover from the stories we lived through. Finding love, getting married and having a family is a story, and so it cannot happen here.'

In spite of what he had seen in the mirror, he couldn't imagine falling in love with anyone who wasn't Lily. Thinking again at the image, and how the five younger adults all resembled one or other of the two older people, he realised that it hadn't been a man with his wife and their five children at all, but a man with his wife, his own children from a previous marriage, and his stepchildren. Was it even possible to love more than once? Muggles remarried after widowhood or divorce, but the only person he had known in the wizarding world who had been married more than once was a serial spouse-murderer for whom being in love had never been a requirement. Most witches and wizards from his world fell in love as teenagers and either got married shortly after leaving school or were heartbroken by rejection or bereavement and never got emotionally involved with anyone again. The teachers at Hogwarts were traditionally the latter, as people who didn't have any children of their own had more time to act as the foster-parents of hundreds of teenagers at any given time.

'What happens to those who want to get married?' Anakin asked.

'They have to wait until they reincarnate.' Anakin blinked, clearly not having expected this. Severus tried to remember how Cheiron had explained it to him, a few months after he had first arrived. 'We are not required to remain here forever. People come to rest here for as long as it takes to discover what true lessons we learned from our experiences, unlearn the mistakes we made, and decide what we want to be next time. Some stay for longer – maybe a few hundred years – to help the new arrivals. But when we decide that it is time to move on, we wait until there is a story ready for us to be born in it, go to the relevant pool in the wood, and dive in, and live a new life as someone new in that world.'

'Could the different incarnations meet each other, here?'

'Yes. They just wouldn't know it, because they wouldn't remember their past lives. Konstantine or I could be reincarnations of you, for all I know.' Severus was fairly sure he himself wasn't a reincarnation of Konstantine, even if they did look somewhat similar. What might Konstantine's next life be like? Even if he was born into a setting where he had loving parents, plenty of money, enough self-awareness to go mad on his own terms and in a way that he chose, access to education and competent mental healthcare, enough confidence to choose for himself what sort of career he wanted to have instead of needing to fit into whatever role society allowed him, and the good fortune to fall in love with someone who loved him, life would probably never be easy for him. But, even if people didn't consciously remember their past lives, they entered the next life as a slightly wiser soul than the previous time round.

What did Severus want in his next life? He still didn't know. If he ever turned back into a human, he would have more options than he currently did as a cat to try out new activities. But perhaps he ought to keep the mirror in a cupboard – or, better still, give it to Cheiron for safekeeping – so that he and everyone else could have a quick look in it once a year or so, just to see what it was now telling them about their deepest desires and to keep track of how their desires changed, without spending enough time with it to become addicted.

He wanted to feel resentful that nobody until Anakin had ever asked him, 'What do you want?' But, in fairness, Cheiron had asked him that, repeatedly, since he came to the Rock, and he had been given everything he had asked for: first, to have a place of his own; then, to be given useful work to do; then, to be allowed to offer Konstantine, and later Anakin, a home with him. But it had been easy to twist each of these in his mind into, 'Cheiron doesn't want me living with him, he'll reject me just like everyone else; I'm just here to be a useful slave with no rights; I have to care about supporting other people but nobody will ever care about me.'

Cheiron wasn't pushy enough to establish a telepathic link, get into Severus's dreams and refuse to get out until Severus was willing to think about what he wanted. Konstantine, quite apart from being a Muggle, had realised early on that both he and Severus felt more comfortable keeping a formal distance from each other. Nutt had suggested that hypnotherapy might help, but had politely withdrawn when he could see that Severus didn't trust that idea. But Anakin had no boundaries. As Darth Vader, he had been willing to do anything to force people to do what he wanted. But, having finally understood that this was wrong, he could be just as obsessive about forcing Severus to decide what he himself wanted.