Disclaimer: I do not own Harry Potter. All characters and settings belong to the lovely J.K. Rowling. All I own is this plot and Cassia.

AN: I know I haven't updated… anything in a while and I'm so sorry, but I keep getting ideas for something else! I'll get to everything as soon as I can. I hope you enjoy this though!

Charlus Potter entered the study where he'd left his supposed grandchildren when Albus came to drop them off and stopped when he heard the argument they were having. The little girl was pinching the bridge of her nose and had her eyes closed as she spoke to her brother.

"So let me get this straight. You and Albus decided to de-age both of us and send us back in time by over twenty years so that we can grow up with our father and stop the war early. Then, Albus wrote a letter for his past self and sent it back with you, so that he could explain everything to our grandfather, so that he and his wife will willing raise us as their own?" she asked, her voice a deadly calm. The boy winced and nodded.

"And do you remember what happened the last time we were sent to live with family that was supposed to care for us as their own?!" she asked exasperatedly. Again, he winced and nodded. Charlus decided to intervene.

"Why don't you enlighten me as to what happened?" he suggested as he stepped further into the room. Both children jumped and the girl glared at him.

"Never you mind!" she snapped, rubbing her temples in a soothing motion. The boy frowned and moved to stand behind her, gently moving her hands out of the way and taking over. She groaned and closed her eyes, letting her head fall back. The boy shot him an apologetic look.

"Sorry, sir, but she gets a bit… testy when she has a headache and potions don't help her." He apologized. Charlus waved the boy off.

"She's in a time she doesn't know and she's been de-aged by ten years. No need to apologize."

Hazel eyes snapped open and the girl snorted.

"Ten years? I've only been de-aged by nine years. Physically, we're both eight years old." She replied tersely. Charlus frowned.

"You look to be six or seven."

She sighed.

"Yes, well, years of being starved and locked in a cupboard will do that to you."

Both children flinched at the suddenly thunderous expression on his face. He apologized, quickly schooling his features.

"Where are the people who did this to you?" he demanded furiously. The boy snorted and dropped his hands.

"Currently? They're children, probably only two or three years older than we are."

The girl sighed.

"So, what are we going to do?" she asked tiredly. Charlus raised a brow.

"Well, I would like to know your names before I call my wife in here to discuss our next course of action."

She blushed and looked down at her feet.

"Sorry. I'm Cassia and this is my twin, Harry." She murmured. Harry put an arm around her shoulders, frowning at her.

"How's your head, Cass?"

She sighed.

"I'll be fine. I just need to sleep it off."

Charlus walked over to them and surprised them both by picking the girl up and carrying her over to the couch. She stared up at him in shock for a moment. Then her pride kicked in.

"I can walk!" she cried indignantly. He smiled down at her.

"I'm aware of that, but indulge an old man, would you?"

Once against she stared at him, then she crossed her arms and huffed.

"When you put it that way…" she grumbled. She stuck her tongue out at her brother when she heard him laughing. He set her down on the couch, a pillow behind her back to prop her up before going to the door and calling for his wife. A few minutes later, Dorea Potter was staring at the two children in her husband's study in shock.

"Charlus?" she asked sharply. He grinned at her.

"Dorea, meet our grandchildren."

She stared at the children, who were now waving at her cheerily, then turned to husband and demanded.

"Explain."

Several hours later, the three had finally managed to explain everything to the Potter Matriarch's satisfaction. Dorea turned to her husband and told him firmly,

"We're adopting them."

Charlus grinned.

"Yes, dear."

Three years later

"Cassia, James, Harry! Hurry and finish packing! We're going to be late!"

"Coming mum!" the three chorused, throwing the last of their things into their trunks and running downstairs. Time with their new family had been kind to the Potter twins. Charlus and Dorea had blood adopted them that night and Harry's once green eyes were now a stormy grey and his sister was no longer a redhead, but she was no less as fiery. She took more after the Potters than Lily Evans now, but Harry hadn't treated her any differently so she didn't care. They'd been put on a regimen of nutrient potions the next day, but now they were the size and height they were supposed to be and got along smashingly with their new brother. James had been thrilled to wake up and discover he had siblings and had become overly protective once he had heard their story. Charlus and Dorea had agreed to tell James to the truth on the condition that he tell everyone outside the family the public story, which was that the twins were the children of Charlus' brother Edward and a muggle and the pair had reportedly been killed by Death Eaters. The twins had then been sent to live with their mother's sister and her husband until Charlus saw their names on the family tree and he and his wife had taken them in and adopted them. The three met at the bottom of the stairs and grinned at each other. They were going to Hogwarts today and none of them could wait to get there. They ran to the kitchen and sat on either side of their parents, who laughed when they started wolfing down their food.

"Slow down," their father chuckled, "Hogwarts will still be there when you get done."

"Mum said we were running late." Harry replied around a bite of toast. Cassia made a face of disgust at her twin, swallowing pointedly before she spoke.

"Harry, don't talk with your mouth full, it's disgusting."

He stuck his tongue out, which was covered in food he had yet to swallow. She gagged and James nudged him in the ribs, shaking his head. It always amused Cassia that James treated her more like a princess than their father while Harry just went out of his way to annoy her. She snorted internally. Well, it was Harry. She'd be surprised if he did put her on a pedestal. Harry grinned at her across the table and she rolled her eyes, laughing when James pouted and exclaimed,

"No twinspeak at the table!"

She and Harry smirked at him before speaking in unison.

"Why not?"

James scowled at them.

"You two are mean."

Their parents laughed.

"Harry, Cassi, stop tormenting your brother." Dorea scolded. The pair bowed their heads to hide their grins.

"Yes, mum." They droned together. Cassia finished the last of her porridge and jumped to her feet.

"I'm going to brush my teeth – back in a minute!"

Twenty minutes later, all three children were dressed in muggle attire and waiting next to the fireplace for their parents to hand them the Floo powder.

"Be careful and remember to enunciate." Their mother warned. The three rolled their eyes.

"Yes mum."

One by one, the stepped into the emerald flames.

James looked at his sister in shock. In three years, the girl had only snapped at him a handful of times.

"Cass?"

The raven haired girl placed her hands on her hips and glared at him.

"What's wrong with you? There's nothing wrong with being in Slytherin! Just because our world's most notable fruitcakes were Slytherins doesn't mean they're all bad. If Harry or I were in Slytherin, would you disown us?" she demanded furiously. Having the situation explained to him from that perspective, the Potter Heir paled and shook his head earnestly.

"Of course not!"

She beamed.

"Good." The smile faded, "Now apologize." She ordered. James sighed and turned to the two next to the window, looking the boy he'd just insulted in the eye as he spoke.

"I'm sorry, that was rude."

The sallow boy eyed him warily, but accepted the apology with a jerky nod. Cassia smiled happily.

"Now why don't we all introduce ourselves and play nice?" she suggested loftily. James immediately agreed, holding his hand out to their companions.

"I'm James Potter."

The boy eyed the hand with suspicion, but with both females in the room glaring at him, he accepted the offered limb.

"Severus Snape."

The redhead beside forced a smile.

"Lily Evans."

Cassia's smile widened.

"Cassia Potter." She told them chirpily, refraining from shaking anyone's hand. She looked pointedly at her twin and the boy beside him. Harry caved first.

"Harry Potter." He offered reluctantly. The other boys glowered at her, but finally gave in.

"Sirius Black." He bit out. Cassia raised a brow, then sat next to him and put her head on his shoulder closing her eyes tiredly. He stared at her.

"What are you doing?" he asked curiously. She rolled her eyes.

"Using you for a pillow, now shush and let me sleep." She huffed. He rolled his eyes, putting his head on top of hers.

"Fine, then you're a pillow too." He groused. She shrugged.

"Whatever. As long as you don't wake me up."

With that, the two fell asleep, the two Potter boys watching the exchange with amusement.

"Fifth year?" James asked. Harry shook his head.

"Sixth." He replied confidently. James cocked a brow.

"The usual, then?"

Harry grinned.

"The usual." He agreed, shaking his brother's hand. Lily and Severus watched the exchange in confusion.

"The usual?" Lily asked hesitantly. Harry grinned at her.

"Five galleons."

Her eyebrows rose.

"On what?"

"What year those two pull their heads out of their arses and start dating." James replied promptly. Lily was appalled.

"You're betting on your sister's love life?!" she demanded incredulously. The two boys shared a look, turned back to her and shrugged.

"We've bet on worse." They replied together. Lily made a noise of exasperation and leaned back in her seat, shaking her head in annoyance. These two were going to drive her insane.

AN: I'm going to skip around in the next few chapters until I get to fifth year. Let me know what you think!