I don't own Harry Potter or any of the characters. Since my OC is related to Harry, the plot will closely follow that of J. K. Rowling, but with my own twist. This chapter might be a little slow since it's just setting up the story before going to Hogwarts. I hope you enjoy!

Cat and Harry felt that they were extremely ordinary children. They lived in a house, went to school, and did chores. There were, however, some strange things about them as well: they didn't know anything about their parents, were forced to sleep in a cupboard under the stairs by dreadful relatives, and unexplainable occurrences followed the pair wherever they went. Perhaps it was these mysterious qualities which helped the two realize they were different from everyone around them. Other than each other, they didn't have friends—but they didn't mind. Each loved the other more than anything; they appreciated the bond they shared and always protected each other. Although they were twins, no one could really tell by simply looking at them. They were both small and skinny with bright green eyes, but where Harry had black shaggy hair and glasses, Cat had wavy auburn hair with nothing to impede her piercing gaze.

For Cat, this day was as ordinary as the rest. Her Aunt Petunia had started breakfast, Uncle Vernon was reading the morning paper, and Dudley was being a typical prat. Harry was fetching the post but something seemed a bit off; he'd been gone much longer than usual. When he came into the kitchen he placed some envelopes on the table, but held onto two of them, and handed one to his sister. She was shocked—they never received letters—yet they each had a letter of their own. Studying the delicate green scrawl she read her name, Miss Catherine Potter, and noticed it was even addressed to the room she shared with Harry under the stairs. She and Harry started opening their envelopes together, slowly breaking the red wax sealing the unknown contents within. Before they could open the envelopes, Uncle Vernon snatched them away.

"What do the two of you think you're doing?" he asked the children mockingly.

"They're addressed to us!" Cat and Harry shouted in unison. "Give them back!" They reached for their letters but they were ripped in half before their eyes.

"Who could possibly want to write to you," their uncle sneered.

Cat had never felt such a strong mixture of defeat, rage, and hurt. Someone wanted to write to her—it was her letter—and all of her joy had been ripped away by her own uncle. She wanted to scream, to cry, to hit her uncle, to do something! But she knew that would only get her and her brother into trouble, so instead she took a deep breath, turned away from her cruel uncle, and walked out of the room. She desperately wished to get away but there was nowhere to go; this was the only family she had. If it weren't for Harry she would be lost and she knew he felt the same way.

"Cat, are you alright?" Harry was the only one to call Catherine by her nickname and it never failed to cheer her up.

"I'm just sick of being here, living with family members who don't even like us, and…" she trailed off, slightly flustered and embarrassed.

"And what?" her brother pressed. He was curious about what she seemed unwilling to say since Cat was always the more outspoken sibling.

"And, I don't know, I really felt like something great was in those envelopes, something that would make our lives better. But now we'll never even know." Cat couldn't hide the disappointment in her voice. Harry pulled his sister close, hugging her tightly.

"Who knows," he whispered, "maybe we'll get another chance."

A few days later it seemed like the Potter twins were getting their second chance. Owls began showing up all over Privet Drive, all of them dropping off envelopes specifically for Cat and Harry. Uncle Vernon was going mad from the unusual situation, shoving handfuls of the envelopes into the fireplace, burning them unopened. But they continued to come. More owls and more envelopes every day until he finally snapped and told the family they were leaving to escape the incessant barrage of post. Cat and Harry were amused by the whole thing; this was all happening on their behalf and they had never seen their uncle so hilariously angry.

The family relocated to a run-down shack built upon rocks and surrounded by water. They had to take a boat to reach the building which helped to convince Uncle Vernon they were in an obscure enough location to be left alone. It was a single-bedroom "cottage" with two tiny floors. When they arrived, Uncle Vernon and Aunt Petunia took the bedroom upstairs and Dudley snatched the single couch downstairs, leaving Cat and Harry the floor. They were used to unpleasant living conditions. The Dursleys had never made the twins feel welcome—their aunt and uncle made them sleep in the cupboard under the stairs even though there were extra bedrooms, their cousin was a constant torment, and no matter what either of them did they couldn't get their relatives to like them even the slightest bit.

All of Cat's worries about trying to get along with her family were amplified around this time because it was her birthday. She had always been envious of other children who got presents, cakes, parties, friends, and people genuinely happy to see them through another year. She had never received so much as a card. She and her brother were the only ones to wish each other a happy birthday and, as much as she hoped for something more, she felt that this year would be just the same.

She and Harry were lying on the dirt floor, drawing a birthday cake just for them. They had never had a cake of their own but had seen plenty for their spoiled cousin, Dudley. They were determined to make this cake even more beautiful and delectable than any he'd had.

"What kind of cake should it be?" Harry whispered. It was nearing midnight, nearly the beginning of their birthday.

"Definitely chocolate," Cat whispered back, "with pink buttercream frosting."

She had always dreamed of having a cake just like this, even if it was only dirt. In her mind it was just right and she dreamily doodled some frosting while Harry added the eleventh and final candle.

"Perfect," they breathed in unison, admiring the work they created together. At that moment the clock in the room rang twelve times, signifying midnight had struck and it was time to celebrate. Cat and Harry looked up at each other, smiling.

"Happy birthday, Cat."

"Happy birthday, Harry." Cat grabbed her brother's hand, squeezing gently. "Let's make a wish," she whispered happily.

Harry nodded, grateful to see his sister so excited. They closed their eyes, paused for a few moments to think of what they wanted more than anything, and then blew out their candles.