Do you believe in soul mates? In people you are just destined to meet, to fall in love with? Do you believe in true love? The kind of love that takes your breath away and makes you beg for more?

I remember being asked these questions when I was younger. I remember thinking "this is insane, how can I possibly know if I believe in all of that when I've never been in love?". I'll tell you what I believe in now, having experienced what I needed to experience to answer.

I believe in destiny, I believe in falling wonderfully, madly in love with another human being. I believe in getting lost in someone's touch, I believe in feeling as though your soul is irreconcilably linked to somebody else. I believe in wanting forever so badly it hurts.

I'm just not sure if you get it.

Early May, 4 years ago - Arizona

Arizona pushes through the overgrown underbrush, wincing as sharp branches scratch her legs. She makes a mental note to drag her brother out here to help her cut a path to the treehouse. When she finally breaks free of the underbrush, she finds herself at the edge of the river. From where she stands, she can see the treehouse hanging out of the tallest tree in the forest. Her face breaks out into the most genuine smile, and she bends over to undo her converse sneakers. She ties them around her neck and walks through the river, which only goes up to her knees. Tim says when he was younger it used to be up to the top of the bank, moving with a force that can only be found in nature. She'd decided she believed him. The sun was out and shining, warming her skin for the first time after a long winter. When Arizona scrambled up the other side of the bank, she shook the dirt off her clothes and smiled at the massive tree in front of her. She ran her fingers over the engraving in the base of the tree. T.R. & A.R.

"You need to see this!" Tim shouted, barreling full speed through the forest.

"Timmy, slow down!" Arizona shouted back, rolling her eyes.

Tim stopped and let Arizona catch up, before smiling a genuine smile and taking off at a sprint again.

"Catch me if you can, fatty!" He teased, causing Arizona's competitiveness to kick in as she chased him down. They reached the edge of the river within seconds of one another, Tim smiling proudly.

"Beat you." He pointed out.

Arizona rolled her eyes and shoved him just hard enough to make him shift his weight to the other side.

"You're two years older than me. And your legs are longer." She pointed out.

"Look!" Tim said, pointing across the river. Arizona covered the sun with her hand and looked to where Tim was pointing. In the biggest tree she had ever seen sat a treehouse. It wasn't your ordinary, rickety treehouse. It was beautiful. She'd have expected no less, with carpenters in the family.

"Holy crap." She muttered, and Tim smiled proudly.

"I know, pretty awesome right? Let's go!"

They crossed the river and came to stand directly in front of the tree house, Arizona looking up the massive tree in awe. When she looked back down, Tim was standing at the base of the tree, pocket knife in hand.

"Is there bears of something out here?" She asked, and he laughed.

"Nope. Just doing something."

He ran his hand over an engraving in the tree, which she could see were his initials. T.R.

"Dad engraved this with me when he made it. I was seven." Tim explained, beginning a carving next to his name. Arizona didn't ask questions, she just watched as Tim's brow furrowed in concentration. After minutes of silence, Tim blew on the area he'd been engraving, and waved her over. He flashed her the biggest smile, and pulled his hand away from the tree.

T.R & A.R.

Arizona didn't speak, she didn't know what to say. She was sure she a couple seconds away from crying a bucketload of tears.

"I know we're not blood related. And I know you've got this life before me, and you've got a mom somewhere. I know it wasn't easy, and I know you've struggled and you've been hurt more times than I can imagine. But back home, right now, my parents, our parents, are signing papers to adopt you. And that makes you my official little sister. This is a Robbins tree house. And if you wanna be, you can be a Robbins too."

Tim doesn't get the chance to finish, because Arizona cuts him off by throwing her arms around him and squeezing as hard as she can.

"Thank you, Timmy." She whispers, and she feels her brother - wow, a brother- squeeze back.

"I love you little sis." Tim says, before letting go and grabbing onto the bottom rung of the step ladder. Arizona takes a second before she follows him, running her fingers along the engraving. She allows her face to break into a wide smile.

"I'd love to be a Robbins." She whispers to no one in particular, before scrambling up the ladder after her brother.

Three years later, and she's still tearing up staring at that engraving. She decides she's no longer mad at Tim for bailing on their regular trip here to go on a date with his girlfriend. He's allowed to go out and have fun, and she's glad he's found someone that makes him happy. At sixteen years old, Arizona has yet to find someone that makes her happy. She hasn't even kissed a boy, and to be honest, she's not sure that she ever wants to. Shaking those thoughts from her head, she grabs onto the bottom rung and begins the slow climb up to the tree house. At the top, she throws open the door and steps inside.

And finds that she is not alone.

Early May, 4 years ago, Callie

Callie has been on the run for what feels like months. In reality, it's probably been days. When her mom's boyfriend came home drunk, she'd made the decision. She'd grabbed those bags she'd packed ages ago and slipped out of her window. She ran until her lungs burned and her legs felt like jelly. She'd slept on the forest floor that night, wearing only a thick sweater and her jacket. The next day, she'd snuck into town and bought two blankets from the used clothing store with the money she'd saved up since she was ten. Then she'd zipped back into the forest, ready to put as much space between her and her home as she could. A couple days later, she'd thrown her backpack into the back of a moving train and hoped on herself. She'd gotten off in the dark that night, to ensure nobody saw her. The train must have cut a path through a forested area, because she found herself in a forest once again. She wrapped herself up in the blanket and wished for the millionth time that she hadn't forgotten to bring matches. Then she drifted into a dreamless sleep.

When she woke up, the sun was out and she packed her supplies and got on the move. She needed to find the perfect place to settle down. She was smart, very smart for a sixteen year old. She'd read up on living in the wild. She knew what to eat, what not to eat, how to collect rainwater. What she was looking for now was the perfect place to turn into her temporary home. She was hoping for a cave of sorts, but she had yet to come across rocky terrain. She'd all but given up on finding anything but trees when she looked up and saw a treehouse looming in a giant tree just beside a river. She nearly dropped to her knees in total shock. A place to live and fresh water? She could not of hoped for more. At the base of the tree, she saw two initials engraved in the bark. T.R & A.R.

"Well T.R. and A.R, thanks for the house." She mumbled, grabbing onto the bottom rung and climbing up the ladder. At the top, she threw open the door and let out a cry of excitement. This was no ordinary tree house. It wasn't creaky and drafty and in danger of falling out of the tree. It was sturdy, built like a tiny house. Inside was a makeshift table made of plywood and a large open space, presumably for sitting or sleeping. Callie took out her blankets and set them out of the floor, rolling one into a pillow. She then put a water bottle half full of warm water on the table. Exhausted, Callie lay down on her blanket and closed her eyes.

The next thing she knew, the sound of the door opening startled her out of her sleep, and deep blue eyes were staring at her in shock.