the_debt_of_time

Mia shook her head. "No. Or, well, yes. I did save their lives once or twice." She
briefly thought of healing James's open Sectumsempra wound and breathing life back into
a recently drowned Lily. "But that's not... why."
"You don't owe her a life debt," Narcissa chimed in. "You boys owe that witch
your lives."
Draco stared up at his mother. "Excuse me?"
"You owe your very existence to Miss Potter, Draco," Narcissa told her son and
then turned her eyes back to Mia. "I remember the last time I saw you. Remembered every
single detail. I had to, of course, seeing that you'd given me a potion recipe that required
very specific instructions. Rose thorns and red clover brewed in the spring and drank under
a full moon."
"You took my advice?"
Narcissa turned her focus to Draco and smiled, this time soft and genuine.
"Obviously."
Mia smiled. "He was still spoilt."
"Which you knew would happen," Narcissa said, waving her words off. "I did,
however, take your advice and kept him out of the control of his father."
"Something that has benefitted the entire Wizarding world, Narcissa."
"Rose thorns and.. ." Draco muttered under his breath and turned his grey eyes
on Mia for a long moment and then looked back to his mother. "Are you honestly telling
me—?"
"You were always talented at Potions, Draco," Narcissa said. "Surely you can
understand."
The uncomfortable look in his eyes said that he understood completely.
"So you gave my mother the recipe for a Fertility Potion," he said to Mia, matter-
of-factly.
It was clear that, until he had said it, many in the room were confused. The moment
he had spoken the words, there was a loud echo of "Oooh" around the room.
"But if that created a life debt, then shouldn't that mean a parent is owed a life debt
by a child?"