Howdy! I'm here again with another Challenge from LightningClan. Maybe I should make a little thing for challenges, but then I would lose all the nice reviews and I don't want to do that. Love you guys!

Anyway, here you go!

My name is Frostwhisper, and I'm dead. I guess you could call me a ghost. After all, no one can see me, I'm able to pass right through other cats, and I watch over my sister to make sure she's okay. How did this happen, you ask? Well, sit down and I'll tell you.

.,.,.,.

"I can't believe we're going to the Moonpool!" exclaimed the excited apprentice beside me. "None of the other apprentices get to go!"

I grinned. "That's because they're all confined to camp. And besides," I added, focussing my bright blue eyes on the path in front of us. "We're only going because there's a rogue wandering around our territory, and Emberstar wanted to make sure Brightshadow was okay." I turned to the black and white medicine cat. "Thanks for letting Sparrowpaw and me tag along."

Brightshadow smiled, her yellow eyes practically glowing with amusement. "Emberstar is right to be wary, and I don't mind. Just remember that the Moonpool is a sacred place to us medicine cats. Anything you see or hear must be kept to yourselves, alright?"

Sparrowpaw nodded, suddenly looking serious. "I won't tell anyone, Brightshadow. I promise."

I smiled at the small apprentice. By our pelts or eyes, you would never guess we were brother and sister. Our mother had taken another mate when my father had died and had given birth to Sparrowpaw a few moons later. So while I got the shared pelt colours of both my mother and father, along with my mother's blue eyes, Sparrowpaw gained the misty-brown pelt, amber eyes, and small stature of her father. There was one thing we shared, however: our personalities. We were exactly alike in our jokes, our attitudes, and the ways we said things. Sure, we disagreed and agreed on different things, but we knew one another so well, it was hard for us not to know what the other was thinking or feeling.

I was surprised to hear I was to be Sparrowpaw's mentor, as well as the rest of WillowClan. It wasn't often that a mentor and apprentice shared blood. But Emberstar explained that he understood how important we were to each other. Our mother and Sparrowpaw's father had died over leafbare by a merciless attack of greencough. Sparrowpaw was everything to me, just as I was to her. We also worked great as a team, proving to be a good pair up as mentor and apprentice.

My thoughts were chased away by Brightshadow saying we had arrived. Both mine and Sparrowpaw's breaths were taken away as we gazed at the area. The Moonpool, which was a complete circle and filled with starlight, was in a small hollow made of smooth stone. My paws slipped into the indented paw prints of the many cats who had come before me to this sacred place. We were the first to arrive, with the other medicine cats nowhere to be seen. Brightshadow thanked us for our escort but asked that we stay at the top of the hollow and a little away so as not to disturb the ritual. Sparrowpaw and I nodded respectfully and stepped away, out of the way of the path up the hill. As we waited, Sparrowpaw and I remained silent, not wanting to bother the medicine cats as they came up the hill. We explained why we were there and they all smiled and said thank you before joining Brightshadow.

A few minutes after they had crested the ridge, I thought I heard something in the bushes. Could it be the rogue? I told Sparrowpaw to stay where she was and followed the noise, lifting my nose to catch the scent. Just as I thought I had caught something, a scream from Sparrowpaw sent me turning rapidly and rushing back to her. I found her on the ground, blood rushing from a gash in her throat, her once enthusiastic amber eyes staring unseeing at the night sky. A shadow was running from the scene; the rogue. A shriek ripped through the silent air, and it took a while to realize my mouth was open and I was the one making the sound.

The medicine cats dashed toward us with Brightshadow in the lead. They all had shocked gasps and horrified cries to utter at the sight of such a young apprentice dead. I couldn't hear anything, my ears having somehow closed off at their own accord. I thought Brightshadow was trying to comfort me as I stared at the only thing that had mattered the world to me. I wasn't screaming anymore, in fact, I think I had begun to cry. Something wet began to flow rapidly from my eyes and pelt the quickly cooling body of my beloved sister.

A star-filled set of paws near her body caused me to look up. A white and pale yellow she-cat was looking at me with her blue eyes. I understood immediately what she was there to do.

"Take me instead!" I begged. "She had so much more life to live. Take me instead of her."

The StarClan she-cat tipped her head to the side. "That would mean that it is you who would die," she mewed. "Are you sure you want to leave her alone?"

I gazed at Sparrowpaw, remembering everything we had done together. "She won't be alone," I replied, looking back into the StarClan cat's gaze. "I'll be watching over her."

The she-cat smiled, seeming to understand more than I let on. "I see." Her eyes began to glow. "I, Iceheart, call upon the powers of StarClan. This tom wishes to trade places with his sister. A life for a life, a heart for a heart, a destiny for a destiny."

I was suddenly overcome with a feeling of great exhaustion, wanting nothing more than to go to sleep. I settled down on the worn path, closing my eyes.

The next thing I knew, I was opening my eyes in a forest so beautiful it took me a second to get used to it. Everything was covered in starlight, and a slight breeze was moving through the trees, making them rustle together. Everything was greens and blues and yellows; the colours of constant Greenleaf.

"Welcome, Frostwhisper," a voice echoed around the tree trunks, "to StarClan. You have earned your rest and peace."

I looked around. So this was StarClan? It was exactly as I had pictured it. As I looked around, I spotted the white and pale yellow she-cat from earlier. She was staring at me with an expression I couldn't read. Confusion, maybe? Or grim understanding? Or maybe it was sadness?

"Why did you ask to trade?" she finally asked.

"What do you mean?"

"You traded places with your sister," she mewed. "I want to know why."

I didn't have to think long. "All I ever really wanted was for Sparrowpaw to have a long life she could be proud of. She couldn't have that if she died as an apprentice half-way through her training. It wouldn't have been fair." I paused for a bit before going on. "We as family members are supposed to put family before all else, and if that means taking their place, then that's what we will do."

"I've never seen a cat do that before, is all," she mewed after a pause. "I think it's very admirable."

I smiled a little. "Thank you, I guess. What did you say your name was?"

The she-cat turned to leave. "Iceheart."

I wandered around in StarClan before I found some area that went down. Growing curious, I followed the path through the sky and found myself at the Moonpool. The four medicine cats were looking at my body as Sparrowpaw got up. Blood was still encrusted over her neck fur, but the deadly wound was gone. As soon as she realized what had happened with Brightshadow telling her, she burst into tears, her body shaking.

I went up to her. "Sparrowpaw, it's okay. I'm here."

She continued crying as though she hadn't heard me. I tried wrapping my tail around her, but it passed right through her back, making my eyes widen in shock. I tried prodding Brightshadow, and then the other medicine cats. Nothing. My tail or paw just slipped right through their bodies. I couldn't touch other cats, but I could still watch over my sister. While I was disappointed I couldn't show Sparrowpaw I was looking out for her, at least I would know. And I could always tell her… later.

Sparrowpaw swallowed. "I understand, Frostwhisper. I understand why you switched places with me." She sniffled, wiping her eyes with her paw. "Okay. I'll be the greatest warrior in WillowClan. In your honour of you and all you did for me. I love you." Her voice cracked at the last word, but she kept strong.

"I love you too, Sparrowpaw," I meowed, knowing she couldn't hear me.

I followed Brightshadow and Sparrowpaw back to WillowClan, hating that they had to carry my large body back all by themselves. WillowClan gasped when they carried my body into camp. A ginger apprentice by the name of Firepaw, who I remembered was Sparrowpaw's best friend, hurried up to her, concern filling her eyes at the sight of my body and the bloodstain on Sparrowpaw's neck. I smiled at the pair of them. Firepaw knew just what to do and say, being kind and considerate to Sparrowpaw's loss, holding her as she cried some more.

Sitting for my own vigil certainly felt weird, and I was happy to learn I didn't get tired. When the vigil was over, and the sun was rising, Emberstar called a Clan meeting.

"It is truly tragic to lose Frostwhisper, but I am happy to hear that he traded his own life, so his sister could live. I know Frostwhisper would want us to move on, so we must give Sparrowpaw another mentor. Hickorywing, you are kind and gracious, as well as one of WillowClan's best fighters, and I know you will train Sparrowpaw well to be a warrior Frostwhisper can be proud of."

Sparrowpaw rose her head to touch the nose of the pale tabby. Understanding and sorrow swam in Hickorywing's eyes, and he smiled at his new apprentice.

I watched Sparrowpaw's training continue for the next couple moons, even nestling in with her at night. Although I didn't sleep, I liked to know that she was safe with me. One night, a sparkling head poked in the apprentices' den as Sparrowpaw was getting ready for bed. It was Iceheart.

I looked up at her. "What are you doing here?"

"I wanted to check up on you," she answered hesitantly. "You haven't been in StarClan since you died, and I wanted to make sure you were okay." She glanced around. "What are you doing down here? Have you been here all this time?"

I nodded. "I wanted to watch over Sparrowpaw. And I didn't want to do that by looking into some sort of pool. I wanted to be sure she would be safe."

Iceheart smiled. "Ah." Her eyes moved to Firepaw, who was already sleeping soundly. "I see what you mean. I haven't been down here for a long time."

I tipped my head to the side. "What do you mean? Is Firepaw one of your descendants?"

Iceheart shook her head sadly. "I didn't have any kits. Firepaw is one of my sister's descendants. I'm surprised you don't recognise my name, in all honesty."

"Should I?"

"I was deputy of WillowClan for a long time. Before I was murdered." Iceheart shook her head vigorously, as though trying to forget something. "But none of that matters now. You need to return to StarClan, Frostwhisper. Your sister will be fine without you."

I looked down at the now sleeping form of Sparrowpaw. "I know. I just want to attend her warrior ceremony tomorrow. Is that alright?" I asked in a teasing tone.

Iceheart chuckled. "Far be it from me to deter you from your sister's warrior ceremony. But after that her destiny is hers to walk. You must not deter her from it."

I dipped my head to her. "I understand. I will return after the ceremony tomorrow."

As expected, Sparrowpaw did very well in her assessment, and as soon as she and Hickorywing returned, Emberstar called WillowClan together. I sat at the front, my chest nearly bursting with pride for my sister.

"Cats of WillowClan!" Emberstar began, his dark ginger tail wrapping around his paws. "It is my pleasure to tell you that Sparrowpaw has completed her training and is ready to become a warrior. There was a time when we were afraid she would not be here, but it is thanks to Frostwhisper's sacrifice that Sparrowpaw has become a worthy warrior of WillowClan.

"I, Emberstar, leader of WillowClan, call upon my warrior ancestors to look down on this apprentice. She has defied death and trained hard to understand the ways of your noble code, and I commend her to you as a warrior in her turn. Sparrowpaw, do promise to uphold the warrior code and to protect and defend this Clan, even at the cost of your life?"

I don't think Sparrowpaw looked more sure of anything than in that moment. "I do, Emberstar."

"Then by the powers of StarClan, I give you your warrior name. Sparrowpaw, from this moment on, you shall be known as Sparrowwhisper in honour of your connection with Frostwhisper. StarClan honours your kindness and your loyalty, and we welcome you as a full warrior of WillowClan."

Though I knew they couldn't hear me, I rose my voice to cheer Sparrowwhisper's name. As I did, she whirled around to meet my eyes for the first time in moons. She could see me. I smiled at her and nodded before spotting Iceheart at my side and following her out of camp and back to StarClan. Sparrowwhisper knew I had been there for her, finally, after all those moons.

.,.,.,.,

Well, I'm afraid I have to go now. What was that? You want to know what happened to Sparrowwhisper? Alright. I suppose I have some time. She became one of WillowClan's best warriors, and eventually earned her place as the deputy. Iceheart wasn't kidding about the 'destiny for a destiny'. A while ago, she told me that it was I who was to be the leader of WillowClan, but my sacrifice caused mine and Sparrowwhisper's destinies to be reversed. I couldn't be more proud of what Sparrowwhisper has become.

Now, if you'll excuse me. I have a life to give. I was thinking a life for family. What do you think?