It always took Severus a few days to adjust to Spinner's End. It wasn't the house so much as it was being away from Hogwarts, the sprawling grounds, the portraits, the people. There were so many people at the castle, and just him at his childhood home. Most left him alone at the castle, true, but there was always the potential that the headmaster or the other Heads would seek him out. None of that in the Muggle neighborhood.
He'd been home for just less than a week. While he still half expected one of his Slytherins to knock on the door to his study in the afternoon, he was comfortable again. It was quiet. The neighborhood was still awful, impoverished and dirty, but his house had become his own private haven over the years. Not even Dumbledore knew that.
Severus had inherited his parents' house at twenty years old. The conclusion to their disaster of a relationship had been statistically inevitable, and he'd hardened his heart to it years before it had happened. He'd been at Malfoy Manor, surrounded by Death Eaters, at the time. They'd toasted the death of a blood-traitor and a foul Muggle man. Severus had mourned his mother in private, and hadn't given his father much thought.
After the war, he'd returned to the house that was his and considered burning it to the ground. But it was where he'd lived when he'd been Lily's friend, and, really, it was all he had. He'd taken it upon himself to transform the place. His father would have hated the changes, which made it that much better.
If somebody were to enter without his permission, they would see the house as it had been. It was a clever illusion. There were dusty light fixtures, pocked floorboards and broken furniture. The whole place appeared dark and dreary. The rooms would seem small, grimy, oppressively closed-in.
If he invited somebody through the illusion, they could see the house as he'd made it. He'd fixed it up the Muggle way with proper tools first, mending the broken banister and bleaching out the rot from the cellar. Then he'd gone further. He'd Expanded the rooms, he'd added light and color and decent furniture. He'd created spells of his own. The front hall had a charmed coat tree that helped him off with his cloak, and the plank hardwood was glossy and clean. The kitchen was small, but the pantry was fully stocked (as it had never been when he was a child). The cellar had been turned into a laboratory, fully outfitted like his space at Hogwarts (though his materials were better quality since he didn't buy them as sturdy stock in bulk for students). The sitting room was mostly library, though there were comfortable chairs and a sofa that matched each other clustered by the fireplace. One of the bookcases in the sitting room hid the door to the stairs (as it did in the illusion of the room, as well, though in the illusion it creaked horribly, as did the steps). The upstairs was airy and homey. He'd gutted his parents' room and turned it into his study, with a big desk and many charmed and indexed file cabinets. His own bedroom had more windows than it appeared to from the outside.
He'd changed more than just the physical space, of course. The sink had been enchanted to wash the dishes by itself, and the cabinets opened their doors as the dishes put themselves away when they were clean. The kettle kept itself full and hot so that he could have tea at any moment. All the food stayed fresh in the pantry, even the things that needed to be stored cold. The fireplace fed warmth into the Muggle radiators (an enchantment he was particularly proud of). His books shelved themselves if he left them out, but not if he set them on his nightstand or on the desk in his office. The curtains opened and closed themselves at the appropriate times. His bed made itself. Anything he put in the hamper laundered itself overnight and sorted itself back into his wardrobe or the linen cupboard as appropriate.
He'd spent years perfecting the charms and adding new ones. It was his ongoing summer project. At the school, he'd make notes to himself when an idea struck, but he mostly focused on his work and on potions research. In the summer, he focused on his house with the occasional dalliance in potions. He bumped along very nicely, in his own opinion.
Then, six days after he'd returned to Spinner's End, a woman (a witch) crossed the line of his wards, walked through his front door, and sat on the edge of the sofa that she shouldn't have been able to see. She smiled at him, and then she vanished, leaving her clothes and belongings behind.
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In London, Hermione Granger, age thirteen, screamed herself awake.