AN: I know I probably shouldn't start another fanfic because I haven't finshed "North's Royals" or "The Darkest Light" yet but I couldn't help it. This is my first cross over ever. This is also my first Peter/Susan fic. So Please be nice in your reviews. If you want to tell me you hate it, that's cool with me but at least tell me what I did wrong okay? I had a hard time deciding if this should be in the H2o just add water or the C.S. Lewis section but seeing as I used C.S. Lewis's Pevensies for this fic, I knew which one I ought to put it under. And you obiovisly KNOW I don't own Narnia or H2o just add water anymore than you do. So here it is H2o just add water, Narnia style!

"Lucy!" Peter called. "Don't lean so far off the banister! You'll fall."

Lucy sighed and gently began pulling herself away from the edge of the boat. Not that she wanted to, but Mum had said that Peter was in charge and anyway, Peter only wanted what was best for her.

The four Pevensies were going on vacation to some place called Mako Island. Edmund had won two tickets at a school event. Lucy who loved to travel had begged to come with him. Of course he couldn't just turn down his sweet little sister's pleas. But there was one rule, Peter and Susan had to come along too.

"How?" Edmund had asked. "They don't even have tickets."

"We'll pay for it." Mr. Pevensie had insisted.

"Why aren't you coming with us?" Lucy had wanted to know. "Peter and Susan aren't grown ups."

"Your father is too busy with work to take a vacation and anyway, Peter and Susan can look after you, it's only for a week. The boat drops you guys off with food and a guide you learn about nature, you come home. It'll be good for you." Mrs. Pevensie had explained.

"I think Susan's mad at me." Peter said as they packed their bags the day before setting off.

"Why?" Lucy asked.

"How should I know? She wont talk to me." Peter said in a confused voice. "She wouldn't even ask me to pass the butter at supper last night, she asked Edmund to do it even though it wasn't anywhere near him."

"I noticed something was up." Edmund agreed. "Did you guys have a fight?"

"No." Peter said. At least not that he remembered. So why was she so mad. It couldn't be about the trip. Susan had already said she didn't mind going and she wasn't being distant with Edmund and Lucy.

This didn't make any sense. If anything, her anger made him feel upset. After coming back from Narnia, Peter had heard Susan crying in her room at the professor's house. They'd talked and promised to tell each other everything so they didn't have to suffer alone. After all, they were both the oldest and could really use someone close to their age to talk to. Now she wasn't talking to him at all.

She's come down from the attic stairs the day before with bloodshot eyes and an angry scowl. But she wouldn't tell anyone what had happened up there. Not even Peter. So much for telling each other everything...

Little did Peter know that Susan had found out the one thing he'd been keeping from her. The one thing he couldn't bring himself to tell her. The one thing that made him different from his siblings. His real last name. Everyone in the area knew Peter Pevensie but Susan had just found out about an orphan baby boy who was once known as Peter Burke before he was adopted by a kind husband and wife who went by the name of Pevensie.

After a while, Susan started talking to him again without being grumpy and he'd wondered if maybe, he'd misunderstood her. Maybe it had just been that time of month or something.

and now they were all setting sail for Mako Island.

Lucy couldn't get enough of the salty sea air. It reminded her of all their sailing trips in Narnia to all the neighboring countries. But Peter wasn't about to let her excitement cause her to fall out of the boat.

"Edmund, Susan, Peter!" Lucy cried pointing ahead. "Look! Look! That must be the island!"

Edmund now started leaning forward. "She's right!"

"This is your guide." The captain told them as they got off the boat.

Susan felt a little sea sick. Edmund was a tad bit dizzy and had to hold his head up from behing overly tired. Lucy and Peter however felt perfectly fine.

Their 'guide' was the scariest looking man they'd ever seen. He was about six feet tall with a dark mustache. Dollars to donuts the man was carrying a gun or two on his person.

Lucy let out a small whimper and hid behind Peter. Edmund tried to hide behind him too before he realized how silly it made him look. Rather he took a step in front of his other sister. There, now he looked tough.

"I am Mr. Pickles." The guide said in a gruff voice.

"Pickles." Edmund laughed, holding his side.

"You got a problem with that, boy?" The guide said glaring at him.

Edmund stopped laughing. It wasn't funny when the guy you were making fun of could smash you like a bug.

"You will all stay together and do as I say." The guide told them. "Or else!"

Edmund raised his hand.

"Yes?"

"Is using threats on other people's children legal?" He asked.

"Does it matter?" The man hissed through his teeth.

"Guess not." Edmund said in a small voice.

"Now march." Mr. Pickles barked, pointing at a hill to the left of them. "We have to hike to higher grounds so we can set up camp."

Susan looked down at her adorable traveling shoes. They didn't have a hike in them. "But my shoes..." She protested.

"Never mind your shoes." Mr. Pickles showed no mercy. "March!"

Susan let out a whimper.

"Su, it's not a long hike, a baby could make it up that hill." Peter told her pointing to the hill they were about to climb.

"A baby doesn't have designer foot wear." Susan grumped wishing she'd had the sense to wear her sneakers on the boat.

When they had made it up the hill, and pitched the tent, Lucy wanted marshmallows. This would've been okay if Peter and Edmund hadn't gotten into a marshmallow throwing fight.

"There goes our snack." Lucy said as Edmund got a piece of white candy hurled at his eye.

"Well, there must be something else you want to do." Susan said.

"Let's go exploring!' Lucy begged.

"Mr. Nickels wouldn't like it." Susan reminded her.

"Pickles," Lucy said. "His name is pickles."

"Whatever." Susan rolled her eyes.

The said Mr. Pickles was sleeping in a chair next to their tent.

"Please?" Lucy begged. "We won't go far."

"Oh, alright." Susan gave in. "But I'm changing my shoes first."

Lucy jumped up and down with delight.

Moments later, they were walking about the small island looking at all the rows of trees and plants.

"Oh I do wish they could talk like the ones in Narnia do!" Lucy said as she spun around to touch the bark of an unfamiliar type of tree.

"This ground we're on now is getting kind of high and slippery." Susan noted we should go back.

"Just a little longer?" Lucy begged taking one more step as she spoke. It was fatal. That one step caused her to fall down several feet into what appeared to be an underground cave of some sort.

"Lucy!" Susan screamed from the opening. "Are you okay?"

"Yes." Lucy called back. "But I hit my foot on a rock. It's too sore to climb back up. Can you come down and get me?"

It might have been wiser for Susan to go get Mr. Pickles to pull Lucy out but she didn't think of that. All she could think of was that her little sister was trapped and frightened in some unknown cave. She had to save her! she just had to.

But as she tried to climb down carefully, she slipped and got herself stuck in the cave too.

"Great!" Susan grumped. "Now how do we get out of this?"

"Look at that!" Lucy gasped suddenly.

There was a large pool of water inside the cave there was a hole in the sky of the cave that you could see part of the sky through.

"Lucy!" Susan gasped. "That's it!"

"What's it?" Lucy asked in confusion.

"That pool might lead to the ocean." Susan explained. "I can go in and swim out the other side."

"But what about me?" Lucy asked. "What if I can't make it all that way?"

"I'll go first." Susan told her. "and see if it's too deep for you or not then you can come after me when I've checked it out."

Lucy nodded. There was no other way. It was already getting dark out and she didn't really want to spend the night in a damp cave.

Susan stuck a toe into the water and then pulled it out. She remembered that her father had always told her it wasn't wise to bathe in a place you didn't know. but what else could she do? She sighed and climbed into the water. It was cool and refreshing. Much nicer than the pool she so often swam in at school. She was a big deal on the school's swim team back there. So this little swim should be nothing, right?

She took a deep breath and swam under the water looking for a way out. In a little while she returned with fairly good news.

"Lucy, it's about a twenty second swim if you go really fast." Susan told her.

"But I can't!' Lucy could barely swim at all. She wished she was still her older queen of Narnia self she could have easily done it then.

"Come on Lu." Susan said reaching her hand up for Lucy to come into the water with her. "I'll be right beside you."

Rather than get in, Lucy started gaping up at the sky. It was a beautiful bright full moon. The water below now shown like a bright while-yellow gem and seemed to have glowing bubbles coming up from it. For half a second Susan felt rather strange. Then she felt perfectly fine after the moon passed from over her.

Before Lucy could get into the water, there was a call from an angry Mr. Pickles. And a rope was sent down from the opening.

Lucy climbed up the rope and out. Susan got out of the pool and followed but it was harder for her because she was so wet and kept slipping.

"What were you thinking?" Mr. Pickles scolded.

"We only wanted to explore." Lucy said softly. "We didn't mean to get stuck down there."

Peter and Edmund were there with him and happily hugged their sisters with tears of joy in their eyes.

"Are you girls alright?" Peter asked.

"We're fine." Susan assured him. "Lucy's heel a is a little bruised but she'll be okay."

After that, Mr. Pickles declared them the worst behaved children he'd ever met and refused to look after them anymore. And with no guide the trip was over. They were all piled back onto the next boat and sent back to London as quickly as possible.

Their parents were more than a little disappointed in them but after a couple of unpleasant scoldings there was nothing left to say about it.

Three weeks later (After being grounded for nearly a month), The children went to the local shore to collect shells and play in the water.

Susan changed into her swim suit behind a rock and then crawled into the water with out being seen. She wanted to get in some swimming practice for school which was starting up again fairly soon.

As she eased into the water she felt like her whole body was turning into water for about half a second. Then suddenly her legs were gone and there was a big fat gold fish tail where they had been.

Lucy and Peter were making sandcastles that Edmund was smashing every time they finished. Suddenly they heard a scream.

"Susan?" Edmund called. "Are you okay?"

"I'm fine." Susan lied weakly. "Really, I thought something grabbed me but it was just a piece of sea weed. I'm fine."

But she wasn't fine. Not even a little bit. She was a fish. Just like the ones that sang for them in Narnia. But this was England. And in England being a half fish was most certainly not fine.

Wondering if drying off would help, Susan got out of the water and grabbed her towel. Everything was back to normal. No more Mermaid fin. What had happened?

She joined the others in building sand castles but wouldn't go back in the water even when they did.

AN: So want do you think of my first cross over? I really would love to know. So click the review button now.