A/N: This chapter focuses on Sheldon alone, but I hope you like it as much as the previous chapters. Thank you again for everyone who's been keeping up and reviewing!

Chapter 8

Sheldon frowned at the door he was facing.

He had been sure that he followed Penny at a reasonably good pace, and although part of his attention was dedicated to digesting recent events, he had been able to keep a view of Penny's blond and bouncy locks in sight at all times.

Pulling his sleeve down to cover his hand, he pulled at the wrought iron handle of the door. It did not budge.

"Drat." Swiveling around, he then considered turning back.

But, to turn back now would be absurd, he reasoned. It would be like dropping out in the middle of an experiment, thus missing out on a potentially momentous discovery.

He noticed the brightness increased significantly behind him, and he turned to face the door again.

Before him glowed an incomplete algorithm diagram comprised of 2 small bubbles, with arrows pointing down at a larger blank bubble. Sheldon eyed the first of the smaller ones.

K times three…squared…

And glanced at the second.

P times three…

"So I must figure out which numerical values to input for K and P…" He whispered to himself. A sudden buzz caused him to jump back a few steps, hand clutching his chest.

"What in the world…" The shimmering algorithm glowed less brightly, and Sheldon squinted at it.

He scratched his chin, analyzing what had just happened, and an idea struck him. He stepped forward and, clearing his throat, spoke up.

"I had a feeling that things would not be as easy as they seemed, as you are a part of me, and I know myself."

Nothing. He proceeded.

"I would have thought that my mind was laden with traps, but our trek through the tunnel had been suspiciously smooth."

He could have sworn the algorithm's light pulsed in response.

"However, I knew it was only a matter of time before I sprung one. This is something much akin to the riddle that the Sphinx presented to Oedipus when he sought to enter Thebes. I solve you, I find out how to get to Princess Peach, or in this case, Penny. Am I correct?"

The diagram's brightness returned, and it was all the affirmation he needed.

Adjusting the strap of his bag, he extracted a marker from his pocket. It was the expo marker Penny had handed him when they were above ground.

Sheldon uncapped the marker, and with a deep breath, began to write. He made furious, swift motions, and the air before him filled with his meticulous handwriting. To anyone who had been watching him, they would have described him as a passionate conductor.

What seemed like hours later, he stepped back from his work, using his hand to swipe away little bits and pieces of what he had scribbled.

The words he had scrawled sprang to life, swimming like his long-forgotten bioluminescent fish, and they fused together to form three symbols:

A fist, which replaced the K. A coin, which replaced the P, and a door, which filled the previously empty bubble.

Sheldon breathed a triumphant laugh. Pictionary…Brilliant!

"Three knocks in three rounds, and three pennies in between. Upon your door I must pound for the outside to be seen. That is my answer."

He knew it was a risk answering in rhyme, but considering everything, he had a feeling that doing otherwise would be inappropriate.

The silence confirmed his suspicion, and the glowing algorithm burst into confetti.

"Well, that was a hoot and a half."

*knock knock knock*

"Penny!"

*knock knock knock*

"Penny!"

*knock knock knock*

"Penny!"

A shuffle and a muffled voice filtered through from the other side of the door.

"Sheldon? What the hell! I thought you were right behind me!" He could hear the impatience in her tone, laced with concern. The door swung open and she stood before him, anxiously biting her lower lip.

"If I had been following any closer, we would have formed quite an imposing T-1000."

Penny gave him a vexed look before she launched herself at him, arms snaking around his slim frame, and pulling him into a tight hug. His arms hovered awkwardly around her, unsure of where to be placed.

All he could think about was hoping she wouldn't let go. Odd.

"Didn't you notice I was gone? I was working on that problem for a considerate amount of time."

"Sweetie…Time doesn't exist here remember?" She sighed. "If I lost you, you'd never…" Penny pulled away from his embrace before she finished and gave him an apologetic smile. "But…you're here now. Are you ok? What happened?"

Sheldon, after an instant, found his voice, and explained how the door would not allow him to exit without passing a trial. He noted the multitude of expressions that flitted over her face, from surprise, to amusement, and then joy.

When he concluded his recounting of the trial, he noticed that they had been standing in front of a tiny shed by a tremendous and stately building.

"Oh. We're outside."

Penny followed his gaze.

"Yup." She popped the 'p'.

"Well, I'm quite glad to be back on topside Sheldonopolis."

"Me too, whack-a-doodle. Oh yeah! I have to find that little froggy and thank him later. If we had gone any farther, we would have ventured into the dark area I pointed out before. We would have become lost." She made a dramatic pose, her hands in the shape of claws. "Forever!"

"Penny."

"Yes, Sheldon?"

"He was a horned frog, not a little froggy."