A/N: Sorry if this one drags a bit, I was trying to find an appropriate pacing for the situation but it made this feel like a beast. I promise things will pick up in following chapters.

"Alright Finn, you went through once, and it didn't appear immediately dangerous. But before I let anyone else near this portal I'm going to have to do a whole lot of research." Bubblegum finished packing up a host of notes, pencils, and a couple books that she'd been pouring over for the past half hour. "Jake, can take me to the library? Maybe Turtle Princess has a book about what's happening here."

"Sure thing PB! Finn, you comin'?" Jake pawed out of the tent and immediately grew, stretching his tail down to wrap up Princess Bubblegum and depositing her on his back. Finn looked up at the pair, and then cast a look to the shimmering portal. He didn't think he was quite ready to walk away from it yet, that girl was entirely too intriguing.

"No Jake, I'm going to stay here and make sure nothing else walks through that portal. It may have all been a trap right? To get us off our guard with weird not-us versions of ourselves." Finn didn't think the small fib was too bad. It was true, something else could walk through that portal, and maybe Finn would have to fight it. He didn't think that was going to be the case though, as the feeling he'd gotten both from the girl and the pink man Gumball hadn't been one of danger. They'd seemed... familiar almost. Finn idly scratched at his hat's burned ear as he started to wonder about the implications of it all. Jake just nodded and tapped his giant head.

"Good thinking Finn! Man would Ooo be in trouble without you! Be careful man, save any big bad guys until I get back alright?" Finn smiled and nodded at his friend and Jake started bounding off towards the library, the Princess clinging to his fur. She turned back to Finn as she retreated away.

"Stay out of the portal Finn! I'll find out if it's safe!" With that, the pair was gone over the dunes and away.

Finn sat in front of the portal, his fingers idly tracing pictures in the sand as his head tumbled over what he'd seen. His brain kept coming back to what Bubblegum had told him, that she'd announced herself as 'Fionna the Human'. She'd even showed her lack of gills to them like he had to her friends. "A human..." He breathed out to nobody in particular. "A real human, like me, and a girl..." He looked again at the portal, grappling with a sudden urge to fling himself through and meet the girl. But he'd heard Bubblegum, and knew that she was probably right. That portal WAS dangerous, the only problem is that danger was kind of Finn's element, he wasn't scared of it. He took a steadying breath and rose.

Well I can at least take a look at it, that won't hurt anything right?

Finn approached the portal once more, this time without his blade drawn and with no battle cry on his lips. He gazed into the shimmering, blue depths and saw nothing but whatever weird stuff the portal was made of. He sighed, having secretly hoped he'd see that girl again.

What if she isn't real? What if she only existed because I went through the portal? Uurgh, I have enough to think about! I don't need this!

Finn put a single hand forward towards the portal, not sure what he was expecting to happen. As it came to rest against the blue film he felt the same pressure he had before when trying to leave. Was her hand against the portal again? He scrambled to his feet and got as close to the portal as he could, squinting his gaze into it. And he was rewarded when he saw the same watery reflection of 'Fionna' on the other side looking back at him. They just started at each other for several long moments, both with a look of curiosity and concern plastered on their faces. Finn finally took a breath and raised a hand, waving at her. He felt a weird sense of relief when she looked at his hand, smiled, and waved back. At least she wasn't just his weird reflection, she seemed to be alive.

Well now what do I do? I can't just not talk to her. But Bubblegum said to stay out of the portal...

It only took Finn a moment to find his answer: she'd told him to stay out, not to not put anything else in! He held up a finger on one hand, and then held up both palms towards her, hoping she'd get his message to wait there. He dashed off to cobble together whatever Bubblegum had left and was relieved to find a pencil and some paper. He ran back with his new tools in hand, scribbling out a quick message to her and pushing the paper and pencil into the portal. He held his breath and looked through, seeing her still standing there and looking at his offered items. She tentatively reached forward and took them, sliding them through the portal without either of them crossing it.

Yes! Score one for Finn!

[*]

Fionna looked at the note she'd received and had to fight hard to keep her breathing steady.

"Hi there, I'm Finn the Human from Ooo! Who are you?"

It was a simple note, and it didn't even take her a full moment to decide to write back.

"Hello Finn, I'm Fionna the Human. I'm from Ooo too, but I don't think it's the same Ooo"

She pushed the paper and pencil back through, a weird thrill shooting up her spine. Despite the strange manner of communication, this was exciting! Fionna loved meeting new people, and if Finn was actually a human... She stopped, not letting herself get her hopes up.

One step at a time girl. One step at a time.

[*]

Finn recovered the paper, reading her part and feeling his own rush. His mind immediately filled with a thousand questions to ask her about herself, "her" Ooo, and the portal. His started to write about 30 different things down at once when he stopped himself. This portal was still dangerous, and a total unknown. Fionna may be an interesting prospect, but Finn had absolutely no patience for being messed with right now. His next question was as brief as he could make it.

"Are you evil?"

He pushed it through and saw her read it, smile, and shake her head as she wrote a response. She abruptly stopped though, and glared knives into him as she wrote the second part. Finn was visibly shaken, suddenly very nervous to read the note she was returning. It came through and he snatched it quickly, not wanting to dawdle near the portal until he read that note.

"As if! I'm Ooo's number one adventuress buddy. And I'm warning you, if you're evil I will jump through this hole and jack you up so bad you'll regret ever opening this portal dude!"

Finn cracked a smile, if nothing else this girl knew how to deal with bad guys.

[*]

Fionna bounced from foot to foot anxiously as Finn read her reply. If he was bad, she wanted to see him tremble in fear so she'd know to grab her sword and go extract some answers. If he was good, she wanted to jump through the portal anyways and get some answers. Gumball's warning floated into her head but she brushed it away. That guy had some nerve talking to her about safety, how many times had she saved his kingdom from his own crazy experiments? Even if he was a threat, Finn didn't look that dangerous, Fionna was pretty sure she could take him in a sword fight. He seemed to have finished writing his response and was pushing it through. She took it and looked it over, feeling relief once more wash through her.

"Not evil, promise! I'm actually my Ooo's number one adventurer too. Small world huh?"

She felt satisfied at the moment with the response; she assumed that if their Ooo had to have an adventurer too than one so similar to herself made sense in her head. She raised the pencil and stopped. There were hundreds of questions she could write to Finn, and yet she didn't want to write anything. She looked around, it had only been about 10 minutes since Cake and Gumball had left meaning they wouldn't even be at the library yet. It'd likely several hours before they returned, and she knew that there was no chance she could just sit here sending notes for that long. She steeled herself as a reckless thought popped into her head. She wrote Finn a quick message and sent it, then quickly gathered her things.

[*]

Finn could only stare at the note in his hand, his breath speeding up and his heart pounding in his chest.

"I'm coming through."

He looked up to see Fionna gone from the front of the portal, and he immediately scrambled back a step and scooped up his sword. He paused for a moment, considered it, and then lowered the blade. He just couldn't believe that she was evil, she'd seemed too nice, too... adventure-y, to be a bad guy. Or bad girl. Whatever. He looked at the portal as it shimmered more and starting to vibrate as the first hint of golden hair and bunny ears poked through it.