Author's Note: Hot damn, what a teaser trailer! Suddenly there's an influx of older!Hiccup related stuff and I'm starting to feel like all my current ideas have become obsolete. In some twisted, morbid way (you have been warned), I guess this chapter kinda fits the occasion, but I don't know. Please excuse me while I lace up my running shoes.

Disclaimer: I do not own Rise of the Guardians, How to Train Your Dragon or Portal/Portal 2.

Hypothesis

Chapter 8: Burning

:: Welcome to the final test! When you are done, you will drop the devices in the equipment recovery annex. ::

Jack and Hiccup shared hopeful looks as they approached the entrance of the final test chamber. The announcement marked the start of the end of their journey, and whatever it was that came after, they would just have to wait and see. But until then...

"Let's finish this," Jack flashed his trademark smirk and winked at Hiccup, getting a confident grin in return.

For some reason, this last test track was pretty straightforward. There were no turrets in sight and they didn't even have to split up at all. The only hazard present was the sea of poison on the floor, matching the main 'theme' of the chamber, which was to maneuver around obstacles while standing together on a moving platform.

It ferried them on a predetermined route through a set of corridors, moving past ledges with buttons and into the path of a few plasma balls, forcing Jack and Hiccup to figure out how to evade them with their portals and synchronize the pressing of the buttons with the platform's constant motion. The puzzles were a little tricky, but nothing too difficult for them to solve.

Soon enough, the end was in sight.

:: Congratulations! The test is now over. ::

The platform hummed lightly as it turned the corner to their right, taking them through an empty grey corridor. Jack spotted a picture of a slice of cake high up on the wall at the far end and he was quick to point it out to the other test subject. The voice had repeatedly promised them a cake at the end of the tests, so it was a sure sign of the completion of their testing experience.

They had made it.

Hiccup laughed with triumph and raised his hand towards Jack, who grinned and gave him a loud high-five before twisting his palm slightly to lace their fingers together. With a sharp tug, he pulled the unsuspecting brunet into a tight hug, stunning his partner only momentarily before he felt thin arms wrap around his waist, returning the gesture eagerly. Chuckling with giddy excitement, Jack rested his forehead against Hiccup's, relishing the feel of the smaller teen in his arms.

"We did it," he whispered with a cocky smirk, ice blue eyes locking onto bright forest green ones. Hiccup nodded and smiled back shyly, and Jack found his gaze slowly being drawn towards the other's captivating lips. Absently, he wondered if they tasted sweeter than the cake they were going to be rewarded with.

Maybe it was from testing without rest for what seemed like several weeks, but suddenly Jack started to feel exhaustion seep into his bones. He pushed against Hiccup, using him as a support, a mixture of immense relief and a rush of affection for the brunet flooding his systems. Despite a few rocky bumps in their companionship, he knew that they wouldn't have made it to the end without each other, and before he even realized it, he was leaning in dangerously close to (and strangely, a little forcefully towards) the other boy.

Hiccup blushed furiously but did not resist, willingly surrendering to the magnetism between their faces as his eyes slid close, their lips just a hair's breadth away –

:: All Aperture technologies remain safely operational up to 4000 degrees Kelvin. ::

Wait, what?

Furrowing his eyebrows, Hiccup broke the spell between them when he pulled back from the hug to stare at the walls with confusion. Warning bells were going off in his mind at the voice's bizarre words, but he had no time to puzzle out what it was saying as Jack suddenly slumped forward, leaning heavily against him with his face buried in Hiccup's shoulder.

"Hic? I – I don't feel so good…" he croaked weakly, his words slightly muffled as his arms dropped limply to his sides, sending his portal gun clattering to the platform.

"What's wrong?" Hiccup asked worriedly, a spike of fear tearing through him when Jack's legs abruptly gave out, causing him to collapse into the brunet's chest. Hiccup's knees nearly buckled from the unexpected dead weight and he gently laid his partner down, immediately focusing his attention on him. Jack was breathing hard with half-lidded eyes as he curled up into a ball, beads of sweat dripping down his face.

"Jack? JACK!" Alarmed, Hiccup shook his shoulder frantically, trying to rouse the unresponsive white-haired teen without success. What was happening to Jack? Why now?

And was it just him, or did it suddenly feel much warmer than before?

:: Rest assured that there is absolutely no chance of a dangerous equipment malfunction prior to your victory candescence. ::

A sharp line on the moving platform appeared between them with a hiss. Hiccup gasped and scrambled backwards, but it had been a mistake to retreat. The metallic surface shuddered and jerked apart, splitting into two halves, leaving Jack's crumpled form sprawled on one and Hiccup on the other as they diverged in their paths. Silently cursing his stupidity, the brunet raced to the edge of his half, reaching out helplessly towards his partner.

"JACK! GET UP!" he screamed, but the other test subject did not stir.

As far as he could see, Jack was heading straight ahead towards a dark chute mounted on the wall, just below the picture of the cake, whereas he was being redirected into another corridor on the left. Where Jack was being taken, he did not know. But as for himself…

Hiccup turned around and his eyes widened at the sight of his destination. His half of the platform was travelling towards a literal oven, the floor of the dead-end room alight with bright orange flames as though it had been doused with fuel and set ablaze. At the rate the two platform pieces were moving away from each other, Hiccup knew that it was already too late to try and make it to Jack, who was quickly disappearing from his line of sight. The corridor walls surrounding them were not portal-conducting surfaces and the other teen was too far away to consider making a jump to his platform. Cutting across the toxic floor was not an option either.

They were being separated, this time for good, and there was nothing Hiccup could do about it. Refusing to give up so easily, he spun around with urgency, his eyes scanning every nook and cranny in the walls as he tried to locate a place to fire his portals and escape. A flash of white caught his attention somewhere beyond a large unrepaired hole in the high ceiling.

Like Jack, it was disappearing fast with his platform taking him closer and closer to the fire. Hiccup knew he only had a small window of opportunity to get a clear shot at what was possibly a portal-conducting surface before he was roasted alive, thrown into the burning room without any hope of getting out with a heartbeat. He lifted his portal gun, intending to make use of his temporary vantage point, but just as he aimed to shoot, his eyes strayed to the still form of his partner. Jack was practically motionless, frighteningly so, and the brunet would have thought him dead if not for the rapid yet shallow rise and fall of his chest as he gasped desperately for breath.

With a jolt, Hiccup suddenly realized that Jack was the one in true danger. Whoever was controlling the facility was interested in the other test subject. That was why he was being disposed of in a fiery abyss while the white-haired teen was taken to who knows where. Jack was important, not him.

Jack was the one who had to be saved.

In light of his revelation, Hiccup understood what he had to do.

:: Thank you for participating in this Aperture Science computer-aided enrichment activity. ::

Jack felt weak, so very weak as the intense heat emanated from the perpendicular corridor drained every drop of energy from his body. He didn't understand why Hiccup wasn't affected like he was, reduced to a panting, crippled mess. Groaning sluggishly, he tried to move but only managed a small twitch of his fingers, his portal gun lying just inches away from his grasp. He realized that he was starting to black out as the edges of his vision blurred with dark spots, and in the distance, Hiccup's faint cries for him were becoming more and more muffled. He could feel his mind starting to shut down, and despite him urging his body to do something – anything, dammit! – he was unable to even formulate a response.

Clinging onto the final threads of consciousness, Jack registered the sound of a portal gun suddenly being fired, something green opening up beneath him, and the sensation of falling.

But the very last thing he remembered before disappearing into the darkness was the sight of Hiccup being swallowed by fire.

:: Goodbye. ::