Big/Lil Sis Competition, Team Luna Lovegood, lil sis: Prompts: Phrase: 'I don't understand,' Plot Device: a promise, Time: dusk

Tonks had vanished the glass of the stairwell window and was leaning outside, gripping the sill with white knuckles.

"What's happening?" asked Ginny.

"It's started," she said.

Ginny flew across the landing to join her. They looked down into the falling night, at the grounds now seething with shadowed figures. Bright spells streaked every direction in the dark. From where they were, it almost could have been beautiful.

Tonks launched herself away from the window toward the stairs, but stopped as Ginny tried to follow, grabbed her arm as she tried to muscle past.

"Let me go!"

"I'm sorry," said Tonks. She held her face stiffly, refusing to look Ginny in the eye. "But you heard your mum. You're underage."

Ginny twisted her elbow in a struggle to pull away. "I've had just as much training as someone who's seventeen. I fought in the Ministry, you were there!"

Tonks glanced toward her and quickly looked back. "Listen, Ginny, if I let you go down there and something happens to you…"

"I bet Professor Lupin feels the same way about you," Ginny shot back, "but you're not about to let him tell you what to do, are you?" It came out before she could think about it, and as Tonks backed up a step, her eyes wide and incredulous, she felt herself flush a little in regret.

"That's different!" Tonks exclaimed. "I'm an adult; I'm a fully trained Auror! You're sixteen years old!"

She was right, of course. Ginny felt it in her sinking stomach. Her mother was right, Harry was right. Watching her brothers, her parents and friends prepare for battle it had seemed obvious that she ought to be there with them, baffling that anyone would think differently, but she couldn't come up with a reason better than "just because."

They were right, maybe. But she wouldn't accept it."I'm going to fight one way or another," she said, moving around to face Tonks head-on. "Do you really want to stand here arguing about it?"

Tonks bit her lip. "Just…" She took Ginny's face in her hands for the briefest moment and tried to smile. "Promise you'll be safe. Your mum'll have my head."

"Yeah," said Ginny automatically, and they hurried down the stairs.

There were people in the next corridor. "The fourth-floor passage ends up here…" She could hear one of them say, and Tonks ran past her as she stopped short at the familiar voice. "… Make sure no one tries— Oh, hello Ginny. Should've known you'd join us eventually."

She rushed to hug Fred and George in turn. "Is everyone alright?"

"As far as I know," said Fred. "They haven't gotten into the castle yet, but it's only a matter of time."

"I wouldn't let Mum see you," said George with a small smirk.

"I don't care." Ginny adjusted her wand in her hand, the feel of it comforting her. "I'm going to help. What can I do?"

Fred gave a bark of laughter. "That's the Ginny we know."

"We've got people guarding the secret passages in case, but it looks as if they're not trying to be sneaky," George said. "Right now the main priority is defending the school. If—"

Footsteps clacked in the stairwell and all three of them raised their wands, alarmed, before the newcomer came out into the corridor.

"Sorry," said Fred, letting his wand arm go slack again. "It's just that you could have been coming to kill us, you know. Don't take it personally."

Percy was otherwise concerned. "Ginny!" he gasped. "I don't understand, I thought you were supposed to stay—"

"You didn't really think she'd sit in there quietly, did you, Perce?" said George. "Our sister? You'd have to be an idiot."

"Well…" said Fred, shooting Percy a pointed look.

"Would you two be serious?" Percy gripped his wand in frustration so tightly it looked like it could snap. "This isn't a game; do you understand the threat we are under right now?"

"Yeah, they do," snapped Ginny before either of the twins could open their mouths. "And so do I, which is why I can't let my whole family run off and fight without me."

"Ginny-"

Percy was cut off by a reverberating scream in the corridor below them and the sound of shattering glass. All four of them tensed. This time there was no mistaking what was coming.

Fred spoke quickly. "I'll go."

"I'm coming with you," said Percy.

"We'll go down lower and help beat the rest of them back," George said, grasping Fred's arm in farewell.

A sinking ship came suddenly to Ginny's mind, water rushing in from the lowest part and rising. Hogwarts was flooding. There was nowhere for them to go but down, into the sea. It was happening so fast that she couldn't make sense of anything, moving or breathing, almost as if she were drowning already.

She was afraid, and ashamed.

"Ginny," George called, his hand thrown out to her. "Ginny, are you coming?"

"Promise they'll be safe," she said.

She couldn't have said this in front of Percy, or Hermione, or her mum, someone who'd have given her a sympathetic pat on the back and pitying eyes. But Fred and George had always known how to talk to her. They'd never treated her as a child when it really mattered.

"I'd like to," said George. "I don't know. But what I can promise you, is that we all know what we're risking, and it's worth it."

He seemed so grown-up standing there, in a way Ginny had never seen him before. Even running their own business, he and Fred acted like overgrown children. Now he was smart and serious, like he was made for this, and what was she?

"I'm a lousy Gryffindor," she mumbled.

"What, because you're scared?" He shook his head emphatically. "I'm scared, we're all scared. If you weren't scared now, you'd be deluded. What makes you brave, you see, is doing what you need to even when you're scared." George smiled at her, a big, genuine smile that had no place in a war. "And if I know you, I know you'll do it."

"Okay," she said.

"You don't have to. If you want to go back, you can."

"No," said Ginny, "I can't." And she and George ran into the water.