The story will be Bellatrix/Hermione as the main couple, with some Ron bashing. I don't own Harry Potter or any of the characters, they are from J.K. Rowling
Prologue
The street was dark. The moon barely giving enough light to illuminate the house, a small tabby cat was looking down the street, with caution writing in its eyes, listening to the sounds of the night, ready to jump at the slightest threat. Its vigil was broken by a small cry behind it, where a basket was hiding in the bushes. Inside was a baby, just a month old. The cat rounded the basket and gently nudge its head to the baby, who calmed at the contact, falling asleep again.
After a while, the cat looked back at the street and deciding it was safe, came out, giving a small jump, the cat turned into a woman, tall, thin, in a black dress with a layer that covered her face. Carefully taking the basket, she began to walk, taking a wand inside her robes, she walked briskly toward the white house which she had visited the week before.
She rang the bell, patiently waiting until the door was opened by a man who had no chance to ask who she was because in that moment she pointed the wand at his face, murmuring something very quietly, the point of the wand gave a small light and the man came to a relaxed state and with a lost look, moved to let the woman entered the house, the witch without stopping climbed the stairs and entered a door.
For a moment the witch allowed herself a small smile when she look at the room, which was decorated like a nursery, soft colors, some stuff toys and a beautiful crib. Satisfied with the place and that her spell had worked making the couple to buy the necessary things. Carefully she left the basket on the floor and carefully lifted the baby, which hug and whispered a song. Tears fell freely, while she hugged the baby. -I'm so sorry Hermione –the witch said in a broken voice –But it's for your sake that I'm doing this, when this is over, when the danger is gone, I promise to return for you my sweet little baby- the witch placed the baby in the cradle, who then looked at the woman with deep chocolate eyes, the Witch stroked her cheek and with regret and sad eyes, left the room.
In the living room, she found the couple, the woman jump in surprised to see a stranger inside her home, but just like the man the witch moved her wand and she went into a relaxed state. Sitting in front of the two, the witch began muttering spells to create memories, create the history of the pregnancy to the birth of the baby that now slept upstairs.
After an hour altering the mind of the couple she send them to sleep. She was almost at the door, but stop to look upstairs again, doubting if what she was doing was the right thing to do, sensing that she might change her mind, she force herself to remember all of her friends that were dead trying to stop the Dark Lord, all of the families broken, the danger and more, that gave her strength to open the door and step to the cold night. With a heavy heart she apparated away.
-/-/-/-/-/-/-/-
Almost two years later, the Dark Lord fall was the end of the war, but it wasn't for the witch, it was time to clean the mess left behind by the psychopath and his followers and the witch couldn't go for her baby. By the time the wizarding world was back on its feet, the witch thought it was too late.
The tabby cat watch the 6 years old Hermione Granger leaving school cradling a big book towards her parents, who were waiting for her with big smiles, the child look healthy and happy, and the witch couldn't take her family away, she waited until they left to turn and leave, promising to leave her daughter have her normal childhood, knowing that in the future they will meet, Hermione was destined to join the wizarding world, and then, when she was of age, the witch will tell her the truth.