A/N This is for the Romance Is A Battle Challenge by la z boy and the Dating a Death Eater Challenge by cookies with milk at midnight. So I hope I do well! Oh, and the setting for this story is this: It's after the war, and everything happened the way it did in the books, but Hermione fell for Draco when they went back for eighth year, and this is right after eighth year. Oh, and I probably won't update this very often… but I WILL update.

Disclaimer: I do not own Harry Potter.

Draco and I had been together for almost a year now, so during the summer I went to visit him for a week. He had told me his parents didn't agree with the relationship, so it was good that they were out of town.

What he didn't tell me was that he had a little sister. Her name was Lacerta, and she was ten years old. She would be eleven for the school year, so she was going to be a first year. Wasn't that great? We would be going to school with Draco's mystery sister!

I was packing my bag with everything I would need for the week. My clothes and some books, basically. Oh, and a toothbrush and some toothpaste. I mean, obviously I would be able to summon that stuff at Malfoy Manor, but I just wanted to pack it. A true Muggleborn.

But that didn't mean I had to take the train to his house, no. I don't think they even knew their own address. So I was going to be picked up by Draco himself. You can't Apparate somewhere you don't know the location of. Obviously.

I walked down the stairs with my full bag and waited on the stairs of my house. A loud "pop" rang through the air, and suddenly there was Draco Malfoy, standing in front of me. He smiled.

"Are you ready to meet my sister?" asked Draco as he held out his arm.

I took it. "Of course I am." And we turned into darkness.

I wasn't used to being the one that had to use Side-Along-Apparition. I was used to being the one that did it. So I was surprised when it wasn't like normal Apparition. It was like being sucked down a tube, while regular Apparition was like being squeezed.

We suddenly stopped, and I opened my eyes. I saw a large mansion with a wrought-iron gate, and I knew this had to be Malfoy Manor. Of course, I had already seen it… But that's another story for a sad time.

Anyway, when we walked through the gate, arm in arm, I caught a glimpse of something moving in the window. That must be his sister.

Draco pushed open the door of the manor and we walked inside. Immediately after the door closed a little girl jumped out of nowhere. She had white-blonde hair and grey stormy eyes like Draco. They were obviously siblings.

"Hi, I'm Lacerta. But you can call me Lacy!" she chirped. Her voice was high and fast and energetic.

"Hello, Lacy, I'm Hermione," I said. I held out my hand and she shook it.

"You seem nice. Draco was right to pick you as a girlfriend. I like you." Lacy said all this very fast.

I blushed. "Why, thank you, Lacy."

I glanced at Draco. He was blushing as well. "Well, why don't we go into the kitchen and get some pumpkin juice, okay?"

"Okay," said Lacy and I at the same time. All three of us went into the kitchen and sat down. Lacy sat across from Draco and I. Draco Summoned some pumpkin juice and poured it into three glasses.

After a while, he started to fidget. "Um, I have to go to the bathroom," he said, and left.

After he turned the corner, Lacy's smile disappeared. "So you're the scum Draco brought."

I was caught utterly by surprise. "Excuse me?" I asked, hoping desperately I had heard wrong.

"You're the Mudblood. You stole Draco from me," she said.

"What?" I asked.

"You heard me. Draco can only have one girl, and that is me. You're just some kid from school that my brother hated. I've been in his life since I was born," she said.

I did the math. "But that's only two years before he met-" she cut me off again.

"It was a long time before he met you. Do you honestly think I'm going to just move over and let some Mudblood move in instead of me?" Lacy was being irrational.

"Are you serious? I'm his girlfriend, and you're his sister. Draco can have two of us in his life!" I argued.

"Oh, really?"

"Really. Give me one reason why he only needs one girl," I said.

"I don't answer to you," Lacy sneered. "You're just a Mudblood. I really thought Draco could do better."

"But you answered my questions before!" I exclaimed. I decided not to mention the fact that she thought Draco could do better than me. That actually stung.

Lacy didn't get time to answer. Draco walked back in the room. "Sorry about that, guys. I hope you two didn't mind?"

Before I could answer, Lacy said, "Oh, that's okay, Draco. We were just bonding!"

I could barely contain my anger. Who was she to tell me to move out of Draco's life? She was ten years old! I was nineteen! I had the authority here! I was the brain of the Golden Trio! And who was she? Just some ten year old. But she was Draco's little sister, too. And if I wanted to appear sane to my boyfriend, this was my battle, and my battle only.

The little devil had better watch out, because the angel was gathering an army.

Day 1

I stayed the night in a guest bedroom on the ground floor. All night, I could hear Lacy cackling in the next room over. Draco was a whole floor above us, so of course he couldn't hear.

I wouldn't let Lacy win. I couldn't let Lacy win. Because if I lost, I would lose Draco, too. And that couldn't happen. I loved Draco. His sister… not so much.

I changed into a scarlet tank top and jeans. I also put some socks on, considering the stone floors that, even in the summer, could get cold.

As I walked out my door to go to the bathroom, I stepped in something wet. Lacy's door was open, so she was clearly up. I looked down. There was water on the floor. I stepped carefully out of it, and went to the bathroom, unharmed. That's when I realized that Lucy must have "accidentally" spilled some water in front of my door on her way to the kitchen. And then I realized that, had I not been wearing socks, I would have slipped and fell, possibly getting injured enough that I would have to home.

The games have begun.

I brushed my teeth and combed my hair, and left the bathroom for the kitchen. When Lacy saw me, her mouth dropped open in shock, probably because I wasn't in pain. Draco wasn't there. Asleep, probably. It was only eight o' clock, after all.

It looked like Lacy was going to say something, but then she glanced at my feet, and saw that I was wearing socks. She shook her head angrily.

Draco came blundering down the stairs. He hadn't changed or brushed his hair. I ran over to him and we kissed. Right in front of Lacy. Draco apparently hadn't brushed his teeth, either.

It didn't matter. I loved Draco, and he loved me. So who cared what a little ten-year-old thought? Draco sat down at the table.

"Good morning, sleepyhead," I told him, and conjured some eggs.

"Good morning, Hermione, Lacy. How are you two doing?" he asked.

"Just wonderful," I said cheerfully.

"We're becoming the best of friends," replied Lacy. I think that may have been going a bit too far. But it's not like I could say anything in front of Draco, right?

"Well, alright then. What's for breakfast?" asked Draco sleepily. In answer I held out the eggs. He smiled and took the plate. I copied it and took one for myself.

"What am I going to have for breakfast?" whined Lacy.

I feigned surprise. "Oh, right. You can't make your own without magic, right?"

"Right," said Lacy flatly.

Wordlessly, I copied the eggs again and handed the copy to Lacy.

"I don't do eggs."

"Too bad, Lacy. Hermione just woke up, and so did I. We're not making you anything else," said Draco.

I felt the same way. But if I was going to act like I thought Lacy was adorable instead of the devil in disguise, I would have to help her. I twirled my wand and came up with some bacon. I handed the plate to Lacy.

She took a cautious bite. Finding nothing wrong with it, Lacy ate the rest. I nodded, satisfied. She could trust me, I didn't play dirty, even if she did.

At least, not yet.

Later that day, Lacy got back at me by hosting yet another trick. I was starting to hope she has forgotten all about it, but this is Lacy we're talking about. So I was eating lunch, and right as I was about to bite into my sandwich, I saw something crawling on top of it.

Wait- crawling? Food doesn't crawl. I slowly took my sandwich away from my mouth and inspected it. I saw a worm crawling calmly on top of what was supposed to be my lunch. Don't ask me how it got there- but I'm pretty sure Lacy was manipulating her magic that she wasn't supposed to even know how to control.

I've always been afraid of bugs. Especially worms. I would never help my mom with the garden because every time I would put my shovel into the ground, a worm would appear.

So I did what I always had done. I screamed.

Okay, so I know that's what Lacy wanted. You don't have to tell me. But it was what I had grown up doing, and I wasn't about to stop screaming because of a worm just because I was at my boyfriend's house.

Draco leapt to his feet and was standing over my shoulder within seconds. "What happened, Hermione? Are you hurt?" he asked urgently.

I glanced at Lacy. She hadn't moved an inch, except to curve her small, thin lips into a smirk. I couldn't have played it more perfectly if I tried.

"No, I'm fine. It's just…. I almost ate a worm!" I yelled. I showed the sandwich to Draco, who curled his nose in disgust, but Vanished the worm with a basic Vanishing spell.

Then he patted me on the shoulder. "Herms, why was there a worm on your grilled cheese?"

I looked at Lacy. She was about to explode- well, implode I guess- from holding her laughter in so long. If I told Draco the real reason, Lacy would have won, and I would have to back off Draco forever.

Because who in their right mind chooses an insane girlfriends over a lovable sister?

So all I said was, "I have absolutely no idea," as calmly as I could. I risked another look at Lacy. Her laughter was replaced by a fearsome glare.

Well, it would be fearsome, if I didn't know what it was for.