Delia Nicola Dagworth had always carried the burden of the Dagworth-Granger heritage. A dark-haired, dark-eyed woman who always wore black outside of a Potions lab (where only an idiot would wear anything but white), it was rare to see her without a very serious expression on her face.
Her uncles had trained her as they'd been trained under the auspices of the Most Extraordinary Society of Potioneers by authorised masters. The founding patriarch of the Society had formalised a preference for having wizards inherit over witches, and her own father had discouraged her, consequently. Then her much older brother, Richard Sky Dagworth, had thrown his Potions education over the railing, changed his professional name to Richard Sky, and become a successful professional Quidditch player, of all things.
At that point, Delia's father had to be grudgingly thankful to his brother (and brother-in-law) for training his daughter. Together, Delia, her father, and her uncles had patched together their family's network of Potioneers, reestablished their supply chains, and, in general, reestablished some of their family preeminence among Potion-brewers. Her father had branched out into so many business interests that Potions had been put on the back flame for nearly a generation.
That was unfortunate, because the Dagworths, starting with Hector Dagworth-Granger, had an advantage in Potions, similar to the one enjoyed by Horace Slughorn - a knack that was actually magical in nature. Slughorn was more well-versed in Potions lore than anyone else in the Society, his hand very steady for his advancing age, and he was unflappable in recovering from an accident, yet the most painstaking Potion brewer alive. And all of that just put him on a par with Delia, her father, and his brother. Her mother's brother was a gifted Potioneer more resembling Severus Snape or Andromeda Tonks - skilful as opposed to magically enhanced, and not at the superstar level of a Slughorn.
Now that the family situation had settled down, Delia had begun to feint at making plans to travel, make non-Potions connections, perhaps even find romance? She was still astonishingly busy every day, but began to see a light in the fog as their Potions network stepped up and began running on its own.
And then, disaster struck.
Suddenly, all of the Dagworths had lost half of their knack. There was, really, no other way to put it. Rather than have them risk the trickier, pricier potions like Felix Felicis and be tossing Malaclaw venom around, she talked her father and uncles into shutting down their part of the business altogether, then practising brewing the least harmful potion she could think of - the Draught of Living Death. Because they had a location to gather Moondew by the barrel, and because they had to use up some of the other ingredients extremely soon lest they spoil, it wouldn't really cost them very much money. And the Draught did have the ability to go wrong: To test it, therefore, she had them all brew, and brew, and brew nonstop, yet at a rate that would normally have nearly zero defects or issues. Where, before, under those conditions, her maternal uncle should have five failures per thousand vials, her father and uncle, three, and Delia herself one, they had a rather neat record of ten, six and two. She tested it as best she could with other potions, and the "loss of knack" held true.
Delia's mother, a somewhat plump and top-heavy socialite, returned home on receiving an owl from her father. Even her Quidditch-mad brother sent in a few guesses and suggestions. One thing that most of them believed was that it was no fluke of magic. Rather, the family was being cursed. It was under attack, either from a group like Britain's Death Eaters, or from a rival Potion selling family, or both. The Dagworths had moved to the Riviera in Delia's grandfather's day, when they were still hyphenating their name. It was a relief, her grandfather said, to drop the Granger sobriquet as they were "a runty pack of Squibs." Nonetheless, they were all brought up to speak British English, and the more isolated members actually only spoke limited French. They tended to identify with Wizarding Britain still, except when the topic of the:Lord Voldemort and his Knights or Death Eaters came up - at that point, they were "well out of it" and "cut our ties to that society."
The family had some rather dark grey artefacts, to be honest, and one of them was a ritually enhanced scryer that had a little in common with a foe glass. Delia's parents and uncles, and Delia herself touched the glass and concentrated on the question: Who is our enemy? Who is taking our magic?
To their great shock, and partial relief, as they'd been meditating in place for over two hours, and were all nearly at the end of their endurance, when an image came, it was - a young girl. She looked to be the age of a starting Hogwarts student, in fact!
The girl's hair was curly in a fly-away fashion, her front teeth were prominent, her eyes were large and dark, and the expression they had reminded her family of Delia herself, though that young woman would not have thanked them for saying so. They stayed silent and unmoving, as often one could hear the person's name if they were sufficiently patient.
Sure enough, after a long wait, they heard what Delia presumed was the girl saying her name to someone - a blurry shape with glasses whose name they couldn't quite make out.
"I'm Hermione Granger," they heard a faint and quiet version of what was probably the girl's voice say.
Now, the whole Potioneer Society/Witch thing had put a strain on the relationship between Delia and her father, but at this, they were of one mind.
A GRANGER! A Granger was stealing the family magic of Hector Dagworth-Granger!
They're a bunch of squibs, they never had the talent, the Dagworths did, even before Hector's time! That's not how family magic works!
Then, the scrying glass caught their eye again. The girl was standing before a glowing manor house, but one the size of a large doll house.
"That's a symbolic house," her mother's brother said, "she's not really there."
"That means," said her mother, looking even more cross than her father, if that was possible, "that someone is using her to establish a new magical House, a House Granger, if you will. And they're taking the nearest family magic they can find to establish themselves."
"What can we do about it?" Delia asked. But it was her father who answered her.
"Not us, Delia. You. My work can keep the family solvent even without Potions, you know that. If you really are up to the job of being the family torch-bearer, finding her and fixing this is your job. You've gotten us to shut down the Potions business. What good are you doing hanging around here, again?"
Delia looked away from her father and glared at the fading image of the girl.
Whoever you are, wherever you are, whatever you think you're doing, I am going to make very short work of you, she vowed.