Prologue

Everyone knows what happened the night of October 31st, 1981, when YouKnow-Who killed Lily and James Potter and made an attempt on the life of their son, Harry. Unsuccessfully of course. The Dark Lord was vanquished, and not long after, Sirius Black, a family friend and Harry's godfather, along with Hagrid, arrived in Godric's Hollow to find the home in ruins, his friends dead, and his godson crying and alone. The men, grief-stricken, rescued baby Harry from the rubble. Sirius tried to take Harry, as his godfather, but the half-giant insisted on following Dumbledore's instructions and taking the baby to his Muggle relatives. Black relented and lent Hagrid his motorcycle for the journey. Hagrid later arrived outside the home of Mr and Mrs Dursley with Harry on Sirius's flying motorbike. Dumbledore was waiting for them, along with Professor McGonagall, to leave the baby with his aunt and uncle, where he grew up for the next century.

However, there is a big piece of the story missing from the records that almost no one knew. Harry was not the only Potter that survived that night. Lily and James had a second child. Aislianna Asphodella Potter was born on June 18th, 1981. She was kept a secret from all except a select few. Minerva McGonagall, Albus Dumbledore, and Severus Snape being the only ones trusted with the information. James and Lily fought for some time over whether Snape could be trusted with the knowledge, as he was believed to be a high ranking death eater in YouKnow-Who's inner circle. As he was her best friend, Lily never lost faith in him and he was eventually named Aislie's godfather.

The night the Potters were killed, Severus hurried to Godric's Hollow in hopes of warning them. Unfortunately, he arrived too late and could only wander the wreckage in anguish. He stumbled into the nursery and, after mourning Lily's death, he frantically searched for his precious goddaughter and whisked her away to safety.

Now the obvious question to ask at this point would be, if Snape arrived at the Potter home first and stole away little Aislie before Sirius and Hagrid ever discovered the tragedy, where were they when Hagrid and Harry appeared in the Dursley's neighbourhood? The Hogwarts teacher did eventually leave the four-month-old on the doorstep of Number Four, Privet Drive next to her brother for the Dursleys to find, and, like Harry, that's where she remained until she came of age to attend Hogwarts, but not before he spent many hours in turmoil. A large part of him hated to let her go. As her godfather, the responsibility for her protection and welfare fell to him, and he had made a promise to her mother to do what was best for her. He simply had to decide what that was. In the end, she was left to be reared by her muggle relatives, where he knew with a heavy heart he wouldn't see her for the next eleven years.

During that time, little Aislie grew into a sweet young girl, in spite of her unfortunate circumstances. Her brother had it worse, of course, being forced to live in the shadow of their odious cousin and everything that came about because of it, however, there were some upsides. Being the only girl in the house apart from Aunt Petunia, meant that there were no hand-me-downs to be had, which meant she was a tad better dressed than Harry. The clothes were still cheap, but they were tolerable, and she believed her aunt secretly enjoyed whenever she needed new ones. When she had told Harry of her suspicions, he confided that he had once overheard their aunt saying she was 'the daughter they never had.' and he teased her good-naturedly from time to time about it. Life for the Potter siblings wasn't always easy or joyful, but together they made the most of it. They split the chores, they helped each other, the even got disciplined together. If one got into trouble, the other would do something to make sure they were both in for it.

Harry was very protective and always looked out for his little sister. Therefore, when it came time for him to go off to school, it scared Aislie. Everything started going downhill when his Hogwarts letter arrived. Uncle Vernon became even more irritable than normal, and after Hagrid appeared, gave her cousin a pig's tail, and whisked her brother off to buy his school supplies, things got worse. The day the family went to London to get Dudley's tail removed and drop Harry at the train station was incredibly hard for her and she silently cried in the back seat the entire way home. The year to follow was the loneliest year of her life.

Mr and Mrs Dursley were quite angry with their nephew, but with him gone off to 'that freak school' as they called it, they took it out on Aislie. She did more chores than she had ever done in her life and the couple avoided her like the plague. If she were ever in the same room, the only acknowledgement she received was a look of wary disdain from the corner of their eyes. The only upsides to it were the new bedroom she now spent most of her time in, and Harry's letters which she had made him promise to write every week. She was always excited whenever she heard the 'tap-tap' of Hedwig knocking on the window. His letters were always told her of some new adventure he and his friends, a red-haired boy named Ron and a girl with bushy brown hair named Hermione, got up to. How she missed him so.

By the time Christmas came around she practically buzzed with excitement at the thought of having him home, even if was only for a few weeks. However, a week before she expected him back, her happy little bubble popped when he wrote saying the Dursleys weren't allowing it. He did send her a quite a few wizard candies and sweets as well as a Gryffindor scarf for her presents, but it wasn't the same. Needless to say, she was crushed.

After that, she began to change.

Her letters got slowly shorter, their tone not quite as happy as they used to be, and Harry noticed. He grew increasingly worried about his sister. After he, Ron and Hermione saved the stone, that worry took root at the forefront of his mind. Having learned about his history, he had never told his friends about his little sister, but they had taken notice of the letters he received every week. They knew he wasn't close to the Dursleys, certainly not close enough to send lengthy updates. Finally, a few days before everyone was set to leave for the summer, they confronted him.

"Harry, who is it that you are always writing to?" Hermione asked suddenly one afternoon as they sat outside. Ron nodded in agreement.

Harry's eyes went round and he hesitated before sighing. "My little sister."

His friends stared in shock.

"Your what?!" They asked in unison.

"Tha-That's impossible!" Hermione exclaimed, "I've read almost every book there is that mentions you or your family and not a single one ever mentioned you having a sibling, let alone another person beside you surviving an attack by You- Know Who!"

"She was only a few months old at the time so maybe no one knew about her. Hagrid looked really surprised when he met her too."

"How old is she?" Ron asked curiously.

"She'll be eleven on the eighteenth."

"So she'll be able to attend Hogwarts next year?"

Harry nodded and watched as the two absorbed the information.

"Wait," Ron looked incredulous, "if the letters are from your sister, why is it you look so worried lately when you read them? I remember at the start of the year you were always really excited when you got a new one. I could always tell whenever you had because you would be really happy for the rest of the day."

"I'm just worried about her." He sighed and laid back on the grass. "Something's different these last few months. I've been noticing it since Christmas but never really had time to think on it much until now. She used to write a full page or more and they were always so happy and full of questions. She wanted to know every detail of what everything was like and what was going on. Now I get barely half a page and the joy is, just… gone. I was really worried about leaving her alone with my aunt and uncle. I just hope they haven't been too hard on her."

"Wow, Harry, why didn't you ever tell us?" Hermione asked softly.

"Yeah, we're your best friends."

"After I found out what really happened to my mum and dad, all the bad stuff that happened with the war, I was scared to tell anyone about her because I didn't know who I could trust. I wanted to protect her."

Ron patted his shoulder. "Your secret is safe with us mate."

"But, Harry," Hermione added, "you do realize that everyone's going to find out about her in a few months though, don't you? If she's about to turn eleven then she will most likely get her Hogwarts letter this year, which means she'll be called to be sorted on the first night."

Harry only sighed and nodded before Ron decided to change the subject.

For the rest of the week, he was anxious to see Aislie again. He could barely sit still on the train and his friends took turns devising new ways to distract him. When they arrived, they got off the train and crossed through the barrier with their trolleys, looking from their families. Ron introduced Harry and Hermione to his parents and sister, and in turn, Hermione introduced everyone to her parents. Harry waved goodbye then went over to where the Dursleys and his sister were waiting for him impatiently.

"Harry!" A small female voice exclaimed. There was a blur of dark hair and suddenly she was in his arms. "You're back!"

"I missed you too, Aise." He hugged her back tightly before loading his trunks into the boot of the car and climbing into the back seat.

When they got back to Privet Drive, he realized Aislie was much changed from the last time he saw her. There were the physical changes of course. She had gotten a bit taller and her black curls were a good deal longer than the shoulder-length they had been when he left, falling in silky tresses down her back. But there was also behavioural changes as well. She had always been a quiet child, but not this quiet. She had spoken hardly a word the entire trip and the hour since they had been home.

"Aise?" He asked softly as he sat next to her on her bed. She looked up at him, green eyes meeting green. "What's wrong? You're never this quiet when it's just us."

She looked down and didn't answer immediately.

"Aisa.."

Still silence.

"Aislianna." She startled at the sound of her full name and looked up. "Talk to me. Did something happen? I've noticed a difference in you since Christmas from your letters."

"It's just been hard here without you." She finally confessed with a sigh.

"I'm sorry. Were they horrid?"

"Just a little bit." He saw the slight smile she gave and grinned too.

The lively girl he knew was still in there. He just had to work to bring her back out. And one thing was for sure, he was never, ever, leaving her alone with the Dursleys again.