Disclaimer: I do not own The Chronicles of Narnia in any way, but I wish I did.
All credit goes to C.S. Lewis, a literary genius.

There is no smut or romance in this. It's just a silly little fluff-fic, so please don't think that I've included any 'Pevencest' whatsoever. I still can't believe that's even a thing.

"Augh!" Lucy bolted upright, her hair plastered to her forehead with sweat, and flung her bedclothes aside. "I – but – oh..."
Another bad dream. She had had many in the past few nights, ever since they had got back from the battle.
Lucy wiped her face, only to find hot, salty tears trickling down her cheeks. This must have been a particularly bad nightmare... she just hoped nobody had heard her. She knew it was silly to think that nobody had, but still she rearranged her pillows and lay down to try and sleep again.
Just moments after the blankets were back around her shoulders, a dark shape appeared at her door. In the moonlight, Lucy could make out Peter, yawning and rubbing at his arms.
"Lucy? Are you all right? Was that you I heard?" he asked, frowning at her. He padded across the floor, his bare feet almost silent on the stone, and sat on the edge of Lucy's bed.
"Yes. Yes, I'm fine. Just another nightmare." She sat up. "It's fine, really."
"But it's not, is it? This is the fourth one this week, Lu. Look at you, you've been crying." Peter gently wiped her eyes with the hem of his sleeve.
"It's fine, Peter, I promise. I'd tell you if there were anything wrong."
She was, of course, lying, but she wanted to seem braver. Peter just gave her a look and took her hand.
"I might have believed you years ago, Lu. But not anymore."
Lucy sat up. "Alright, so I might be a little frightened. But don't worry, Peter. I'll be fine."
"And I'm the King of England," replied Peter, mocking her slightly.
"Well, you are the King of Narnia." Lucy grinned, but she still felt tense.
The dream – it had seemed so real. She supposed all dreams did – or dreams of dreams – but that didn't make her feel any better.
"As the High King, I command you, my dear Queen, to give me a hug. Then you'll tell me about this dream."
"Oh, but Peter!" Lucy began, but her older brother pulled her into an embrace and muffled her protests. "I'm not little anymore. But alright, I'll tell you."
"Thank you, milady," Peter said, taking up his Old Narnian dialect. He sounded so much more grown up when he spoke like that, quite unlike himself.
"It was, just before the Witch was defeated. You and Edmund were fight, and somehow I ended up on the battlefield. Oh, Peter – it was awful. I could smell blood, and the screams were just terrible. How did you manage out there?"
Peter's arms wrapped tighter around his sister. He himself had barely managed to cope, and he was so much older than her. "Oh, I expect Aslan had a hand in that," he lied.
"I saw Edmund and the Witch – and she got to you, but Aslan didn't come. And the cordial wouldn't work – and Susan said I was useless and a traitor, just like Edmund, and, and..."
Her words grew faster, more hysterical, and tears spilled down her cheeks. Peter rocked her back and forth, trying to comfort her.
"Lu – Lu, it's alright. I'm here, and Edmund is here, and you know Su would never call you a traitor." His voice softened, and he took Lucy's hand and placed it gently against his chest. "See? Still beating. It was all just a bad dream."
"You won't go away?" Lucy asked.
"I won't, I promise. I'll stay right here, and I'll scare the bad dreams away."
The girl seemed comforted by his words, and relaxed in Peter's arms. As he rocked her, she seemed lulled. Her eyes closed, and she fell asleep with a small smile on her face.
Peter tucked the blankets up by her chin and slid in beside her. He would stay with his sister, forever, keeping her safe from the darkness.