Meeting Cordelia Naismith had been the first good thing that ever happened to Severus.

In fact, they had been quill-friends before they met in person. They had commented on each other's letters and articles in potions journals, and then taken to writing personal letters to other (by hawks and falcons, as most owls dislike intercontinental flights). By the time that, at the end of Draco's second year, Silvanus Kettleburn announced that he wanted to retire from teaching Care of Magical Creatures, Severus already knew not only that Cordelia was a Magizoologist who rode a pet Hungarian Horntail dragon named Achilles and that she was looking for a new job. He knew that she was a half-blood like himself, her mother a No-Maj doctor and her father a wizard who had died in a portkey accident; that many of her friends at school had thought she was weird for not being interested in riding hippogriffs; that Achilles had befriended her when she was lost in Death Valley National Park on a family vacation as a child and he was fleeing from an abusive owner, he had insisted on becoming her familiar, and they had been best friends ever since, and that this was what had led her to work in magical conservation over the various other careers she had considered when she was younger; that she was Severus's age; that her mother kept asking if she had met any nice wizards lately, but that the one wizard boyfriend she had had was emphatically not nice and the relationship had ended badly several years earlier.

Severus, in return, had told her as much of his life as he dared: that he was a half-blood too, with a witch mother and a Muggle father, and had grown up in a Muggle town where there was only one other magical child, a Muggleborn, and that they had been friends when they were younger but grown apart when they went to Hogwarts and were Sorted into separate Houses, that he had been lonely without Lily and become friends with people in his own House whom Lily didn't approve of, leading her to spend even less time with him, and that when they were sixteen he had insulted Lily so badly that she never forgave him, broke off their friendship entirely, and had eventually married the leader of the gang who used to bully him, and that she and her husband had died young. He wanted to tell her everything, but he couldn't talk to anyone about most of it, let alone to a witch he had never even met in person – even if he felt that he was already falling in love with her.

At any rate, he had suggested to Dumbledore that they should offer Naismith the job of Care of Magical Creatures teacher. Dumbledore hadn't paid much attention, as he had already decided to offer Hagrid the job, but when Hagrid was suspended for allowing a hippogriff to injure Draco, Cordelia (and Achilles) arrived – and was an immediate success. It helped that, unlike Hagrid, she was a good teacher, and was under no illusions about how dangerous magical creatures were. Just because Achilles was well-trained for a dragon and wouldn't eat anyone without her permission didn't mean she assumed that he was harmless, let alone that dragons in general were nice, friendly animals. A few of the more troublemaking pupils, at least among the pure-bloods (the Muggleborns and most of the half-bloods had grown up with American films and television programmes) tried to claim that they found Cordelia's American accent as hard to understand as Hagrid's Forest of Dean accent, but overall, she was a much-loved teacher and nearly everyone wanted her to stay.

Severus, in particular, wanted her to. She was the first real friend he had had in the staffroom, the first colleague who didn't remember him as either a boy they used to teach not so long ago, or as that weird nerdy kid who used to get bullied by James Potter's gang all the time, and who was possibly a Death Eater. Cordelia just accepted him as a normal person. And while Severus wasn't keen on animals, especially dragons, he had to admit that Achilles was well-behaved as long as Cordelia kept an eye on him, and seemed to like Severus.

He was glad that they had never exchanged photographs. This way, he knew that he liked Cordelia because of who she was, not because she had red hair like Lily. She didn't seem to be put off by Severus's appearance, either. Maybe to someone who lived with the ugliest and most savage breed of dragon in the world, Severus didn't look too bad by comparison.

Unfortunately, Cordelia didn't want to stay. She had research to do around the world, and while she loved many things about Britain (even rain and snow!), she found most things about British wizarding culture completely insane. And, quite possibly, the way that Severus, just before she was due to leave, had begged her to stay and marry him, had put her off.

By the next time Severus encountered Cordelia four years later, he had killed Albus Dumbledore, made himself Headmaster, hired two vicious Death Eaters as teachers and banned Muggleborn students from attending the school, and was the most hated Headteacher ever, which said something considering that Dolores Umbridge had appointed herself acting Head just a couple of years previously. Cordelia was one of a number of foreign witches and wizards who had come to Britain to help the resistance fight against Voldemort, help persecuted Muggleborn witches and wizards, and protect Muggle areas from Death Eater violence.

They faced off against each other in a few battles over the course of the year. She refused to let Achilles flame him. Once, a portrait reporting to him from a resistance location described hearing Cordelia's colleagues arguing with her about this – 'Just because you fancy him doesn't mean he's not a Death Eater! You don't think it's like some Muggle fairy-tale where there's a buried hint of good left in him and you can redeem him, do you?' and Cordelia replying, 'No. I think he's chosen his path and nobody is going to make him change his mind. Severus Snape is a very stubborn man.'

When they next met close enough to talk to each other, it was because Achilles had broken down part of the Shrieking Shack to find Severus lying on the floor in a pool of blood, after Voldemort's snake had ripped his throat open. She cast a quick healing spell, and then asked, 'Do you have an antidote?'

Severus gestured to a pocket of his robe containing a bezoar, which he was already too weak to extract. Cordelia fed it to him, and then, as he began to revive, asked quietly, 'What's the plan?'

'Plan? The Dark Lord has almost completed his triumph. All he needs is to make Harry Potter come to him…'

'We don't have time for this,' Cordelia said. 'I know you're working to defeat Voldemort. Is getting Harry to come to him part of that plan?'

'Yes – I think so. I had to give him some of my memories – there wasn't time to explain in words. If he bothers to view them, he will know what to do.'

'That sounds a very big "if",' Cordelia said. 'Nothing personal, but Harry didn't like you or trust you four years ago, even before he was convinced you were on Voldemort's side. And if you want to prove to him that you're telling the truth by showing him your memories – well, won't it occur to him that a skilled wizard can tamper with their own memories, so you could still be lying?'

'Fortunately, Potter doesn't think that far,' returned Snape, with a faint return of his old smirk. Then he turned serious again. He no longer knew precisely what Dumbledore had told him the plan was, but he had a horrible suspicion. 'I think – I don't remember any more, but I think Potter is meant to die. There is – some kind of link between him and the Dark Lord which means that he must die for the Dark Lord to become mortal and vanquishable.' And it was Severus's fault that the connection existed in the first place.

'That's Dumbledore's plan? To make a teenager hand himself over as a human sacrifice?'

'I think so.'

'That's sick!'

'Agreed.'

'Why are you letting Dumbledore tell you what to do, even now he's dead? He made you kill him, didn't he?'

'Yes. He was mortally wounded from putting on a cursed ring. He had planned that I should kill him discreetly with no witnesses, at a convenient time, but – events got in the way. But as to why – it's because I don't know any other ways of getting rid of the Dark Lord.'

'Didn't he get nearly killed before? Wasn't he incorporeal for years?'

'Ye-' but Severus never had time to finish his sentence. Three Stunning spells hit him, Cordelia and Achilles.

'Thank you, Severus,' Voldemort said when he regained consciousness. Cordelia was still stunned, and, like Severus – and Harry Potter – securely bound and gagged. Achilles, also bound and muzzled, was starting to regain consciousness, but drooped despondently at seeing his human helpless.

'It appears you were worth more to me alive than dead after all, at least for a little longer. Don't worry; I will be more merciful than your true master. When I have wiped the boy's memories, I will keep him as safe as if he were my own child. True, he may never recover functionality, but he will live. You, however…'

Potter struggled to his feet, presumably with some hair-brained idea of intervening. Achilles, who had clearly been neither as groggy nor as despairing as he pretended, snorted fire from his nostrils, scorching the boy's forehead badly and knocking him into a dead faint. Next, he turned his flame on Voldemort, and didn't stop until the Dark Lord's reconstructed body had been reduced to ashes. As some of the Death Eaters began to surge forward to attack the dragon, Achilles turned his flame on them next, until the survivors fled. He might have liked to go on longer, except that by this point Cordelia had woken up and signalled to him through their bond that enough was enough.

Severus was spared Azkaban on the testimony of Cordelia, the Death Eater witnesses Achilles hadn't killed, Dumbledore's portrait, and – once Potter had woken up in St Mungo's hospital and could confirm what had happened – the memories Severus had given him, which had been still lying in a Pensieve in the Headmaster's office.

Suddenly, after a year of hating Severus, everyone wanted to praise him. It felt more of a punishment than anything else. He deserved Azkaban, deserved to be sentenced to the Dementor's kiss. He had tried to send a teenager to die – admittedly, one who was no longer a child but an angry youth who was disturbingly happy to torture people with magic in a moment of rage, but still a boy it was his duty to protect. He had passed on the prophecy to Voldemort which had been the reason Voldemort killed Lily, the reason Lily's son was left with part of Voldemort's soul lodged in him until a dragon's fire had exorcised it (leaving his face even more scarred than before). He was the reason the boy had been brought up by Petunia and her ghastly husband and their bullying oaf of a son (not that he liked Potter or cared about him, Severus told himself, but he knew how it felt, being a half-blood wizard child brought up by uncaring Muggle relatives). And now Dumbledore – and Minerva McGonagall and the rest of the Hogwarts staff, both living and dead – wanted him to come back and be Headmaster for real rather than as Voldemort's puppet ruler. It was obscene.

He fled, leaving a short note reminding his colleagues that he had tendered his resignation at the moment where he had thrown himself through a window to escape because Minerva was throwing daggers at him. To rub it in, he left a small pile of gold to pay for the cost of repairing the window.

None of his surviving former colleagues – in fact, no witches or wizards apart from Wormtail and Bellatrix Lestrange, both now deceased, and Narcissa Malfoy, whom nobody on the Hogwarts staff counted as a friend – had been to his house, so none of them would know how to teleport there. He wasn't on the Floo network. The postal address – 39 Spinner's End, Cokeworth, LE65 2WZ – was listed in his parchmentwork at Hogwarts, of course, and any owl could find him, but he wasn't convinced any of the human staff knew how to use a Muggle atlas to find out where Cokeworth even was. He should be undisturbed to settle into a routine of re-reading every book in the house for as long as he could be bothered to care what he read, and then drinking himself into oblivion when he was too depressed to focus any longer. With proper potions ingredients, he could have brewed a painless poison that would have killed him instantly, but he didn't deserve that mercy, any more than he deserved to be a wizard. Drinking himself to death on super-strength lager that tasted disgusting, like his Muggle father, was a fitting end.

He did get one owl from Hogwarts, from Minerva, stating that Dumbledore really did want him back as a successor, but was willing to grant him a year's paid leave, and please would he nominate a teacher as acting Head? He scribbled a quick note nominating Pomona Sprout. From what he had seen in the battle just before he threw himself through a window, he didn't trust Minerva to be fair to any Slytherin students, let alone the children of Death Eaters. Filius Flitwick couldn't even keep his students from bullying members of their own House, and Horace Slughorn, while opportunistic enough to be free of House bias, was only interested in students he thought could be useful to him when they grew up. By default, it had to be Pomona.

He fed the owl a mouse, sent it off with the message, and fell asleep, hoping to be undisturbed for the next twelve months, by which time he would probably be dead long before he ran out of reading matter and had to renew his membership of Cokeworth Library. If he went anywhere, it would only be as far as the off-licence.

He hadn't expected to be woken by a knocking on his door. He ignored it. There was a flash of flame at the window. Dragon-flame.

Severus sighed, and hauled himself to his feet to open the window. 'Are you insane?' he hissed. 'What are you thinking of, bringing a dragon into a Muggle area? Why are you even here?' Somehow, a fifty-foot high winged lizard seemed a lot bigger standing in a street in a Midlands town than he ever had at Hogwarts.

'In answer to your first question, probably,' said Cordelia. 'Everyone back home thinks so. They wanted to keep me in until the mind-healers could identify what spell you'd used to convince me that I was in love with a former Death Eater. What I was thinking of – Achilles is even better than an owl at finding people. It's okay, there's a Muggle-repelling charm on him. Why am I here – I still hadn't answered your question from four years ago.'

'What? About getting married?'

'Well, do you still want to?'

'Don't ask that yet,' he warned. 'Not until I've told you everything.'

'Okay. Have you got any coffee?'

'Only instant. And there's no milk or sugar.'

'Sounds fine.'

So Severus made coffee, and they sat down on the slightly damp and mildewed sofa, and he told her everything, over several rounds of coffee and – after a trip to the corner shop, because it wasn't right to have no food to offer a guest – a packet of chocolate digestives. By the end, he asked, 'Well? Are you disgusted with me, now you know?'

'No. Anyway, a lot of people have wanted to tell me their life story lately. The last one was Dumbledore. He says the truth is even worse than the version Rita Skeeter invented. If you ever come back to Hogwarts, maybe you should ask him about it. He says you're not as different from him as you think. Personally, I think he projects a lot of his own guilt onto you.'

'It doesn't matter. I'm not going back.'

'Fair enough. What are you going to do?'

'Is getting married still an option?'

It was, and so the next question was where they were going to live. Achilles needed somewhere he could fly freely without being spotted by Muggles, and Cordelia was about to start work at Hogwarts in September. She was sharing two part-time posts, one as Care of Magical Creatures teacher (since Hagrid had to combine this with his job as Keeper of Gates and Keys, being full-time carer for his young half-brother, and working in human/giant diplomacy) and one as Muggle Studies teacher, since she was amazed at how little most pure-blood students knew about Muggles. She had been planning to live in the castle, with Achilles roaming in the Forbidden Forest, as when she was a supply teacher, but if Severus was interested in getting married, they could rent a house in Hogsmeade. Or, alternatively, she could move in with Severus here, and Apparate to Hogsmeade each morning and walk to the castle from there.

Severus didn't want to live anywhere near Hogwarts. On the other hand, his house was a miserable place and, while that didn't matter when it was only somewhere he went to be miserable in, it wasn't a fair place to inflict on anyone he loved. Still, Cordelia didn't blame him for not wanting to be near reminders of his time at Hogwarts. Over the summer, they took everything in the house to the rubbish dump, stripped off the horrible wallpaper, dried the place out and repainted it, and bought cheap but decent-quality second-hand furniture, much of it from charity shops. At least once a day, Cordelia apparated to Scotland to see Achilles. The bond between dragon and rider was too deep ever to disappear, but a dragon whose human neglected him could be heartbroken, and might turn rogue.

In the meantime, once Cordelia's visa was processed and she had leave to remain permanently in the UK, they got married at the registry office, with the witnesses two Muggle neighbours of Severus's who had known him slightly since childhood, were used to seeing him around when he came home for the summer, and seemed relieved that he had found someone to love, without, thankfully, being friendly enough to invite him round for coffee.

It was late August when Narcissa Malfoy invited herself to visit. In her arms was a baby with silver hair with a hint of blue. 'Severus, I have to ask a favour of you,' she began.

'Does it involve assassination attempts, vows which will kill me, or joining in whatever is Draco's current ambition?'

'No, only – it's my niece here. Delphini Lestrange. Well, you know Bella died, and her husband is in Azkaban, and he says Delphi isn't his anyway – he says Bella claimed the Dark Lord was the father, but that was probably just wishful thinking – and Andromeda's bringing up her little grandson as it is, without dropping yet another orphaned baby on her, and besides, well – with a werewolf for a father, Teddy could turn out to be, well, dangerous – and Lucius and Draco and I have been taking care of her since Bella died, but Lucius says I'm neglecting Draco…'

'Draco is eighteen. Plenty of men his age, or not much older, are already fathers. Besides, I thought you always wanted a larger family?'

'Please – she needs love, more than Lucius can give anyone who isn't his own child. And – well, people will all say she's the Dark Lord's daughter, and she's sure to face prejudice because of that – she might be bullied when she goes to school, and if she's kept out of sight and homeschooled, that's just going to make everyone suspicious. Isn't it safer for her if she's brought up by the one man everyone can be sure wasn't on the Dark Lord's side?'

'I need to discuss this with my wife,' said Severus. 'When she comes home from visiting her dragon.'

'Your wife? You're – married to the dragon-lady? I'm sorry, I didn't realise – this changes everything…'

'Why?' retorted Severus. 'Do you not trust Cordelia to be a good parent?'

'No, no, it's not that, only – well, everyone says dragons have the instinct to eat young girls, and – it's not safe, bringing up a little girl in a family with a dragon…'

'Achilles has been Cordelia's pet since she was a child herself, and he is absolutely devoted to her,' retorted Severus. 'He would never harm anyone Cordelia likes. And as for being bullied at school, I will see to it that it doesn't happen.'

'You'll see to it…? Is it true, then? That you're going to return to being Headmaster?'

'Yes. After I've taken a year of parental leave. In the meantime, if you have any concerns, may I suggest that we Apparate over to Hogsmeade now to see how Achilles takes to the new member of the family?'

Delphi screamed loudly at the discomfort of being Apparated for the second time in a few minutes, and threw up as they arrived in Hogsmeade High Street. Narcissa grimaced – she had never liked dealing with mess from Draco when he was that age, either.

Thankfully, Cordelia was sympathetic, and happy to cuddle and soothe the squalling baby. Achilles bent down to nudge the tiny creature gently with his snout, seeming almost overawed by her. There was no question about it: the four of them were going to be a family.

'I suppose we'd better start looking for a house here,' said Severus. 'It's no life for a magical child, growing up in Cokeworth.'

'Is it even possible for her to be Voldemort's child, do you think?' Cordelia asked later, as they sat in a hastily-rented room at the Three Broomsticks. 'Wasn't his revenant body made with part-reptile DNA? I wouldn't have thought he'd even have human gonads any more.'

'I don't know. She doesn't look like Bellatrix or Rodolphus, but she doesn't look like Tom Riddle when he was human, either.'

'It doesn't matter. She's ours, now. Poor kid, you've had a lot of upheaval lately, haven't you? Well, now you've got a mom and dad who are going to be here for you forever – I hope.'

They planned to wait a couple of years and give Delphi time to settle in before giving her a baby sibling. However, even magical contraception doesn't always work, and by December, Cordelia found that she was pregnant, with a baby due in August. It wasn't particularly bad timing. There would be time for Delphi to get used to having both parents at home over the summer, and for the baby to be born, before Severus took up his duties as Headmaster and Cordelia took her year of maternity leave looking after the two children. According to the mediwitch's scan, the new baby was going to be a girl as well.

'Shall we choose one name each for her?' Severus suggested.

'Why not? I'd like Elizabeth, after my mom. What about you?'

Severus wondered. He didn't particularly like the name Eileen – or rather, he didn't want his daughter's life to go to pieces the way his mother's had. Not Lily – too many sad memories. He tried to think of a happy memory, as he once had when learning to cast a patronus. He remembered one summer day in his last year at primary school, when he was ten and the teacher had decided it would be a good idea for the class to read a proper grown-up play instead of just children's stories. The play was about a girl who disguised herself as a boy and went into the forest with her cousin and their clown friend to search for her exiled father, and found a boyfriend, a wrestler who wrote awful poetry.

'Rosalind,' he said. 'I like that name.'

'Rosalind Elizabeth Snape. That works. Do you like that name for your little sister, Delphi?' Delphi beamed uncomprehendingly.

What none of them could have planned on was Delphi being kidnapped in July. The Aurors investigated, but couldn't find any clues – it could have been anyone from Death Eaters wanting to make sure the heir of Lord Voldemort grew up to honour his memory, to anti-Death-Eaters wanting to hunt down anyone who was possibly related to the Dark wizard. Severus was frantic with worry, but did his best to juggle all the administration necessary for the start of the new school year with taking care of Cordelia.

Until he came home to find that Cordelia and Achilles had disappeared, too.

They reappeared a few days later, looking exhausted but. By now, Cordelia had a baby in each arm, the younger of whom was swathed in bandages. As Severus unwrapped them, he realised that they weren't just makeshift nappies and baby clothes. Rosalind Elizabeth had the healed scar of an obviously canine bite across her body – one which would surely have bitten her cleanly in two, or at least punctured her vital organs, if the attacker hadn't been trying not to kill.

'Werewolf?' Severus breathed.

Cordelia nodded. 'Captured – gave birth while – tied up. Sent Achilles to – find Delphi – he came back in time to rescue me – not enough time to stop them biting. He burned through my ropes – helped me find my wand – could heal the wounds.'

Of the all the worst things that could happen… This wasn't the worst sort of worst at all, Severus realised. Voldemort could have won. He, Severus, could have been sentenced to the Dementor's Kiss. Cordelia, or Delphi or Rosalind or all of them, could be dead. Having a daughter who was a werewolf, when he still had nightmares about werewolves, might never be able not to be frightened by the fact that his daughter was a werewolf, might never be able to love her the way she deserved, but knowing that he did at least have the knowledge to brew wolfsbane potion for her – that was the sort of worst he could live with. Yes, maybe he would never be able to look at her without being reminded of Remus Lupin – but then, Lupin hadn't been exactly a bad person, just a misfit who had become part of James Potter's gang because he was desperate to have friends, just as Severus had become a Death Eater because he was desperate to have friends. He just needed to make sure Rosalind wasn't too isolated, and had more opportunity to make good friends.

By the time Rosalind was five, Severus couldn't believe that he had ever worried that he wouldn't be able to love her. She was a bright, curious, adventurous child who was interested in everything around her, and had plenty of friendships with other children in the village, though she was frustrated at not being allowed to stay over at a friend's house if it was full moon, especially as she didn't like having to keep her condition secret. After all, nobody in her family minded – Cordelia thought it was fascinating watching how a werewolf child grew up, Delphi loved having a sister who turned into a puppy at full moon, and Achilles doted on her. He adored Cordelia, liked Severus, and was gentle and well-mannered with Delphi, but Rosalind was his favourite person apart from Cordelia – perhaps because he somehow understood that she, like him, was a monster.

In character, Rosalind was mostly human, but, perhaps inevitably, with some dog-like traits. She preferred long walks or runs to broomstick-flying (though she learned to enjoy dragon-riding so as not to hurt Achilles' feelings), loved games that involved chasing balls (which became socially acceptable when, in her second year at Hogwarts, she became Seeker for the Hufflepuff Quidditch team), was deeply loyal to her family and protective of any member of them whom anyone seemed to threaten (especially Delphi), talked in excited exclamations that were almost barks, and took longer than most human children to understand socially acceptable behaviour and privacy. And she had to restrain her instinct to chase cats (though in this it helped that she had Achilles as a role-model, seeing him restrain his own urge to chase humans).

When Delphi was sixteen, she went missing again. Cordelia didn't disappear to look for her this time – but fifteen-year-old Rosalind did, taking Achilles with her.

When the two girls came back, Delphi looked embarrassed at having caused so much trouble, but Rosalind was both tearful and angry. 'Mum, dad, you should've talked to her about – everything! She ran away because she found out that she was possibly the daughter of the Dark Lord and she was scared that it meant she was going to turn evil! She nearly tried to kill herself, and then she got captured by slavers and – and Achilles died! Because he ran into a dragon-slayer who said he was the same dragon who'd eaten her sister, a really long time ago, like in the last century! And – and we couldn't even bring his body back to give him a proper funeral, because when he died, when the dragon-slayer cut his head off, his body all burned up and turned into red sparks! All there was left is this stone thing that was in his head! That's all that was left of him!'

Cordelia hugged the two teenagers, and Severus hugged all three women. 'Poor Achilles,' said Cordelia. 'How did he behave? Was he angry? Frightened?'

'No, he was – sort of calm, and sad,' said Delphi. 'He just – bent his neck down so the dragon-slayer could reach to chop his head off. I think he thought he deserved it.'

They buried Achilles' stone together. He had been the one who had brought the family together. None of them would ever forget him.