Something snaps in the back of Draco's mind during the battle of Hogwarts, when he sees his friends falling to the ground and has to remind himself that they won't be getting up again. He's ashamed when his parents beckon him to join the Dark Lord and the Death Eaters as the dangle Potter's body in front of the survivors like a taunt. He has to stop himself from retching when Voldemort welcomes him to their side, stop himself from turning and running, from defying his parents for the first time in his life. And as his parents smuggle him away to safety, Draco really and truly hates himself, hates them, hates the life that he has always known.
He leaves Malfoy Manor as soon as he can, but it still takes about a week of sneaking around the massive house at night trying to collect his belongings without anyone noticing. He places an undetectable extension charm on the book bag he used to use at school and stuffs everything in there as quietly as possible, emptying his closets and dressers and nightstands and bookshelves. He sleeps very little, not wanting to see the faces of the dead, and bags are starting to form under his eyes, but if his parents notice anything, they do not speak of it. When he has collected everything he thinks he might need or want, and a few others just in case, he slips out in the middle of the night, leaving a note on the dining room table with only two words scrawled in his intricate handwriting - good bye.
He doesn't know where to go, he's never had anywhere else, except Hogwarts and Malfoy Manor, so when he apparates to Diagon Alley, he merely wanders the empty street until the first beams of sunlight spread over the tops of the buildings and the shopkeepers come out, unlocking their doors and lifting the blinds in their windows. By lunchtime, he has made his way to the Leaky Cauldron, and although it is not somewhere his father would ever have deigned to stay, this quickly becomes Draco's first home away from Malfoy Manor, and he lives in room number seven for almost six months before he finds a flat in London that he likes. He works, even though he doesn't need the money, because he likes being independent, likes not going to Gringotts to withdraw money from the vault his parents created for him and continually stock with gold. He likes not being dependent on his family for the first time, getting a chance to be something for himself.
He meets Astoria Greengrass in Diagon Alley, nearly knocks her over as he reads and walks at the same time, not seeing her standing in front of the Magical Menagerie, gazing at a particularly beautiful black and white cat stretching in the window. Draco checks every day to see if the cat is still there, and a month later he buys it for her as a gift, and she names him Nox, and although he insists that he is not a pet person, he loves the cat as much as she does, sneaking it milk when she's not looking. And when Astoria moves into Draco's spacious apartment, Nox curls up between their feet each night.
As the years pass, the serpent and skull branded into his arm fades into a scar, but Draco still finds himself wearing long sleeved robes and sweaters to cover it, not wanting anyone to see the hideous mark that mars his skin, not wanting to remind himself of the things he did to earn it. Astoria massages the sore tissue there, easing the discomfort that sometimes tingles there like a phantom limb, the memory of the fire that burned when the Dark Lord summoned his servants. She tells him that she forgives him for the things that he did, although she is not the one he needs forgiveness from, and she insists that the world forgives him too, for being a young boy raised to believe the wrong things. She offers him small, reassuring smiles until he believes her, and until one day he learns to forgive himself.
Their wedding is small, very legal, and not the boisterous affair it is in some families. They are happy, of course, overjoyed, but they are also reserved, preferring small shared touches and intimate moments to loud singing and dancing and drinking. It takes a great deal of convincing from Astoria before Draco agrees to invite his mother and father, but she tells him that one day he will regret it if he doesn't at least try to include them, and although he privately thinks she is wrong, he knows when to concede. She is, of course, right, and there comes a day when he finds that he is glad they were there, toasting their son's marriage and bright future.
When Astoria tells him she's pregnant, he is immediately more panicked than excited, and he sinks into a chair, holding his head in his hands and messing up his neatly combed blonde hair. She looks at him, worried, and he faces her with eyes full of fear and thoughts of inadequacy. He doesn't want to be the kind of father Lucius was, doesn't want his child to have that kind of life, imbued with superiority and hatred and false pride. So many children his son or daughter will encounter are going to have actual reasons to be proud of their lineage, but him, what can his child brag about? A grandfather who boasted of being among the closest servants of the Dark Lord during his height? A father who fought for the Dark Lord despite having reservations? Astoria assures him that his child will love him and he will be a good father, and he can't help but believe her when she looks at him with such confidence. When he holds Scorpius for the first time, his doubts fly away, because this kid has him wrapped around his finger already, and he knows he would do anything to give him the best life imaginable.
Scorpius' childhood is very different from Draco's. It is full of laughter and smiles and running through the hallways as fast as possible. Draco plays quidditch with his son in the backyard every Saturday, and plays chess with him every Monday. They build forts and play "dragons" and make such tremendous messes that Astoria glares at Draco with a look that clearly states he'll be cleaning up, not her. They have fun, but Draco also teaches his son to be a respectable person - to take pride in his appearance, to study hard, to speak and write well, to keep company with people who will push him to be better, not bring out the worst in him. When Draco sees Scorpius waving to him from the same car on the Hogwarts Express as little Rose Weasley and Albus Potter, he glances over at Harry and Ron and thinks secretly to himself that, while the three of them may never really get on, perhaps they have at least raised children who are better than themselves and won't walk around hexing each other left and right. Perhaps he has finally done something right. He thinks he has.