Author's Note: I apologize for the late submission. I plan to follow this chapter up soon to stay on schedule.

Chapter 3: Descent

Kurisu found the so-called "Doctor" up one flight of stairs, striding down the hall while holding his device up in the air. She ran to catch up with him, then slowed her pace as she drew level with him.

"Who exactly are you?" she demanded.

Without breaking stride, the man shot her the briefest of glances before answering, "I told you. I'm the Doctor."

"That's not an answer," Kurisu protested. "What's your name? Where are you from? Who do you work for? What are you doing here, really?"

The man pointed his device from one side of the hallway to another. "Is this an icebreaker?" he grumbled. "I hate icebreakers. I'm against icebreakers. What'll you want next? A 'fun fact?' Or maybe a trivial opinion about food?" He came to a door and pushed it open, starting up a flight of stairs.

"Keep your food opinions to yourself," said Kurisu, following closely behind. "and stop dodging my questions."

The man abruptly stopped and whirled around to face her. "The Doctor. Gallifrey. No one. Actually, technically UNIT, but that doesn't count. And saving the world. No –" he amended, starting and stopping on the stairs, " – multiple worlds." Then, just as abruptly, he turned back around and hurried up the stairs.

Though Kurisu could keep up with the pace of his movement, she couldn't keep up with the barrage of odd answers. "What do you mean, 'multiple worlds?' And how exactly are you saving them?"

"The way I usually do it," the man answered without looking. "One person at a time. Starting…" He slowed to a halt. "Here."

Kurisu stopped with him and looked around. They were on a landing, but the entrance to the next floor was still a few stairs above them; there was nothing around them but the walls of the staircase. "Where, exactly?"

"Right there." The man nodded toward the wall next to them.

"...There's nothing here," said Kurisu.

"Yes there is," the man insisted, nodding toward the wall again. "It's right there."

"There's nothing there," Kurisu repeated.

"Really?"

"Yes!"

"You haven't looked."

"I…" Kurisu blinked. "I did look."

"No. You didn't." The "Doctor" fixed her with a piercing grey stare as he said, "You've stopped, and you've concluded, but you haven't looked there."

For a third time, he nodded toward the wall next to them. This time, Kurisu made to turn toward it – and found her head stuck, as if she were refusing to budge. As if reading her mind, the "Doctor" continued, "Perception filter — a kind of camouflage that doesn't make it invisible, but induces the observer to merely look away. If you weren't looking for it, you'd never find it, and even if you were, it makes every effort to turn you away. So focus. Take it slowly. And look…out of the corner of your eye."

Slowly, Kurisu tilted her face and, willing her eyes to move, gave the wall a sidelong look. At first, she saw what she expected to see: a plain, white, unassuming plaster wall. But she kept her focus on it, and slowly her eyes were able to make it out: a vertical, jagged crack, about a meter long, and faintly glowing with a dim white light. The longer she looked at it, the more uneasy she felt.

"A perception filter, and a crack in the universe," the man muttered. "Nothing new, but I still don't care for them.

Kurisu swallowed. "Is that…"

"The mosquito's nest," the man confirmed. "Wait. Do mosquitoes have nests? The wasps' nest," he amended. "The adder's den, the bear cave. The creature's lair. You know what they say, don't you? 'Let sleeping adders lie?' 'Don't poke a sleeping bear?' "

"Something like that," Kurisu agreed.

"There's only one thing to do in a scenario like this."

"…Which is?"

The man raised his blue device. "I'm gonna poke it," he declared. And before Kurisu could protest, he stepped back, pointed it at the crack in the wall, and activated it with a whir and a light.

Kurisu shielded her eyes as the dim light from the crack suddenly flashed much brighter. When it faded, Kurisu looked at the wall again. The crack had grown and widened, now just large enough for a person to fit through; but still nothing could be seen through the crack, as light continued to pour out of it.

The man slowly traced his finger down the outside of the edge of the crack. "Just a small one," he noted. "Leading to a hidden pocket universe. Not the big, universe-shattering kind. At least, I don't think so. It'd be a bit embarrassing if I were to step through and be erased from the universe — again."

"Um, what?" Kurisu shook her head. "Wait, you're going to go in there?"

"That's the plan."

"You can't just step in there without knowing what's on the other side," Kurisu pointed out.

"Good point," the man admitted. "That'd be a bad idea."

"Right," began Kurisu.

"Completely reckless. Highly inadvisable," he added.

"Exactly."

The man nodded. "Goodbye," he said. He stepped into the crack and vanished from sight. Kurisu stared at where he had been, openmouthed.

What the hell?!

She looked around, not really sure what she was looking for. No one else was around, and she'd told Itaru and Mayuri to stay at the apartment. She turned back to look at the crack, which still unnerved her the longer she looked.

She groaned. "I really hope I don't regret this," she decided. She stepped forward and entered the crack in the wall.

The first thing the Doctor noticed when he came out on the other side of the crack was that his surroundings looked like they were drawn by a child – a child pretty decent at drawing, to be fair, but one who paired an unpracticed, imprecise hand with an avant-garde imagination. Random heart shapes floated in the air; flowers sprang up with innocent unrealism; even the floor itself was paved with crayon – and coincidentally, it was broken up into narrow, precipitous stair and floating platforms (below which was a dark and impenetrable void – not really fitting in with the vibe of the other decor). If the OSHA-violating facilities weren't disturbing, the jittery, irregular movement of the pastel environment added to the unease. What should have been a happy childlike wonderland instead felt wrong, off to an unnerving degree. When hearts and flowers sprang into existence at random spots, "surprise" described them less accurately than "jumpscare." The floating platforms, which moved about but lacked predictability, felt less "obstacle course" and more "death trap." And topping it all off was the unceasing chittering echoing throughout whatever space this was. Who was chittering? Where were they? The questions had no obvious answers; sometimes, the imagined threat is more frightening than the visible danger.

The Doctor glanced down at his device. Instead of a continuous whine, it was now beeping, with the light on the end flashing in time. He took a few steps forward, until the "floor" before him ended and the treacherous floating platforms began, and the pace of the beeping and flashing slightly increased. He grimaced.

A noise from behind him caused him to whirl around, pointing his device toward whatever made it. Through the crack emerged the girl with red hair who had been pestering him before. After settling her footing, she looked up, saw the macabre drawings around her, and went pale. "Yep," she breathed. "Definitely a mistake."

The Doctor stared. "What do you think you're doing?"

"Following you," the red-haired girl answered simply.

"I don't know if you missed the cue earlier," said the Doctor, "but this is the part where things get dangerous."

"If you're lying," said the girl, "then you're plotting something further and I'm gonna see exactly what you're up to. If you're not lying, then I want to know exactly what's happening to Okabe and how you intend to deal with it." She crossed her arms. "'Poking an adder's nest' doesn't exactly inspire confidence."

"Trust me, I'm an expert in these matters," the Doctor rebutted her. "Now go away."

"I don't trust you," the girl replied. "That's exactly why I'm here."

He shrugged. "Suit yourself. But don't blame me if you fall into this…bottomless pit over here." With that, he reached into his jacket pocket and tossed something onto one of the nearest floating platforms; it landed with a small 'splat' and stayed there, moving along with the platform. "Well, that's a relief. They look like clouds; I'd hate to throw away my jelly babies and have them fall through." He waited for a few seconds; then, when the platform returned to closer to him, he leapt onto it with a grunt, bent over, picked up his item, and returned it to his pocket. He then started stepping and leaping from platform to platform, until he reached a stretch of solid floor on the other side of the chasm. "Oh, stairs," he noted when got there, noticing a staircase some twenty yards out. "I appreciate you taking it easy on me."

He was about to proceed down said stairs when he heard a yelp some distance behind him. He turned to see the red-haired girl wobbling on one of the "clouds" before steadying herself. The Doctor watched as she, too, navigated the platforms until, at the final jump, she landed on the stable floor behind him.

"Well, look at that," the Doctor commented. "You've started to master 'reckless and inadvisable' already. Hopefully," he added as he started down the stairs, "it won't get you killed."

The red-haired girl hurried to catch up to him. "And what about you?" she countered. "Not afraid of getting killed?"

"It's possible," said the Doctor, "but not historically likely. And anyway, if I do, it's no biggie. Wouldn't be the first time."

"The first time you…?"

"Died. Try to keep up, will you?"

"You're saying you've died before?" the red-haired girl asked incredulously.

"Just over a dozen times," the Doctor confirmed. Then he frowned. "Wait. But if I count that business in the confession dial…maybe several billion times? But I don't really remember all that…"

The red-haired girl shook her head. "Literally none of what you're saying makes sense," she declared, raising her hands in frustration.

"You're in a crayon-drawn pocket universe housing a creature that sucks out emotions remotely," the Doctor pointed out. "None of this should be making sense to you. That's what you get for interning without my permission."

"If this is an internship," the girl responded, "you're not doing a great job of on-boarding me."

"What part of 'without my permission' don't you –"

Both the Doctor's speech and steps came to an abrupt halt at the bottom of the steps, and the girl nearly failed to stop herself from crashing into him. About thirty yards out in front of them, the little pastel flowers that had been ominously lining their path became flowers that blazed with flames that seemed similarly unreal, or surreal — burning, but not being consumed. A ring of such menacing plants formed around a much larger flora — a red-leaved tree-like form, with some sort of glowing mound pulsing at its roots. Oddly, the tree and its branches seemed collapsed somehow, as if the normal erect tree was somehow lying down, trunk, branches, and all. The chittering in the air seemed to be at its loudest here. Perhaps it was these flaming flowers, or perhaps it was this tree; the more the Doctor stared at it, the greater his unease became. Unseen by him, the red-haired girl looked upon the tree and trembled slightly.

"What…is that?" she managed to ask while keeping her voice level.

"Mosquito tree," the Doctor breathed.

The girl blinked. "What?"

The Doctor held up his device, which was now rapidly beeping. "Mosquito." He pointed it at the huge mass in front of them, and the beeping rose even higher. "Tree."

He approached the tree slowly, still pointing his device at it. The device changed its tune again, this time reverting to a mechanical whir. As he approached, the chittering grew louder, and more and more resembled something like laughter.

"Oh yes," the Doctor said, his words suddenly taking on a much graver note. "Laugh while you can. You think this is funny? A little game of hide and seek, maybe?"

"You're talking to a tree." The girl's uncertain tone belied her jest.

"Par for the course," he replied, before continuing, "It's not funny. You have endangered human life, and that has consequences. It's not a game, and I am not your playmate. I am the Doctor."

The tree began to…move. Its branches began to unfurl like a twisted umbrella frame, and its trunk began to rise, looking less like a trunk and more like a long neck. And at its "head" was its treetop, adorned with large, flame-hued leaves, with a center that looked like a burning, angry eye. The girl surreptitiously wiped her palms on her jacket; but though the temperature had begun to rise, it wasn't only heat that was causing her to sweat.

"Did that get your attention?" the Doctor continued, seemingly unfazed. "Or are you merely responding to my encroachment of your space? I don't know if you can understand me, but on the off chance that you can, I am offering you this one warning. That world out there" — he gestured behind him — "you've encroached upon it first. Its inhabitants cannot be your food; they are under my protection. So withdraw, and never bother with that world again. Otherwise, you will have to reckon with my reprisal."

The "head" of the tree rose to full height. The temperature of the air rose to furnace-level.

"Your choice!" the Doctor shouted. "What'll it be? The easy way, or the hard way?"

The chittering stopped.

Then the head of the tree shot forward…and screamed.

It was an unnatural, even inorganic sound. It was both high and low-pitched at the same time. It was, needless to say, loud. The two intruders both clapped their hands over their ears.

"Right," the Doctor muttered grimly. "It's always the hard way."

"Nice speech!" the girl called out. "Now do you have a plan?"

"Oh yes," the Doctor replied as the tree reared back its head. "A great one."

"And what's that?"

He turned around and, with a dash, grabbed her hand. "Run!"

That was when the tree threw itself at them.