A/n: Oh hai multi-chapter slash-fic, number 3 out of 1203412341234... o_o

Okay so, this is the continuation of Believe, which will make this a little easier to follow if you read it. Otherwise, all you have to know is that as a human, Jack lived in Hiccup's time on Berk, and in this universe Hiccup essentially takes the place of his sister.

Which means this first chapter is gonna be pretty angst-ridden. The rest will be largely fluff and bromance, with some serious-ish stuff in-between. But yea.

1. Believe

He ran.

Snow leapt around his woolen boots as they sank into the mounds of white and sprang back out again, step after burning step. The only sounds in his ears were the shrill rasps of his own voice as he gasped for air, and the bursting ache of blood thudding through him like a trembling drum under the blows of a thick mallet.

He was almost there.

The sharp winds bit into his face and struck at his eyes, until his cheeks burned red and the edges of his sight pooled with tears. Droplets escaped the pinched cusp of his eyelids in hectic streaks, all the way down to the open gash on his chin. Everything shook, everything screamed, but nothing his body said could overtake the cries of his heart.

So he did not stop.

Finally, he could see it. The loom of houses renewed the boy's grit as he heaved each throbbing leg towards the Viking village. He watched the structures seem to grow as he approached, until he was running among them, scrambling through the whitened roads, passing frowning neighbors and wandering animals. The chieftain was never hard to find, towering over everyone in his bear furs and plated armor.

Where was he, where was he, where—

There!

"Hiccup? What are you – son, what's wrong?"

Stoick's vast hands steadied his tiny shoulders as the boy tried to muster enough breath to speak.

"He – he – he – he..."

"Who? Come on – who, Hiccup?"

"...H-he," the boy tried, tried to make the words come, but they fell like the points of spears on his dry tongue.

"What's the matter with you, boy? Out with it."

He swallowed.

"We were – the lake – it – the ice – he f-fell... he fell in..."

"...Who, Hiccup?"

The little boy's breath wouldn't settle, and his rushing blood couldn't slow.

"You have to get him out," his hoarse voice pleaded. "He's in the lake. Jack fell in, you have to go!"

Why wasn't the chief stirring? Why was he looking at him like that? That same tired, troubled face he wore when-

...when Mother left.

The boy froze. He let one long, heavy breath go, and a strange, dull calm came over him. All the nerve that kept him on his feet long after fatigue should have buckled his legs, that forced a horrible truth from his reluctant lips – it all slipped away now, leaving in its wake a child too weary to cry anymore.

The ice parted, and he fell.

Water scorched his lungs like flames, scraped past his throat and nostrils with pitiless might. He swallowed in the lake, and it swallowed him back.

Half a minute, and the pain ended abruptly as it came.

Then nothing.

Thought stilled, flesh paled, and within, an eighteen-year-long beat fell suddenly silent...

Moonlight pierced the freezing blue depths, and the abandoned shell of a boy drifted under its glow. The life it once knew was lost to a barren realm, far beyond human reach.

But not beyond the sweeping grasp of the Moon's ethereal beams.

Slowly, the rolling tufts of chestnut brown began to blanch, silvery-white streaking across the length of each billowing strand. Even in the dark brows beneath the whitening bangs, tiny hints of pale hair crisscrossed with the brown. The body floated up towards the ice-encased surface, russet cloak round its neck rippling gently after.

A finger twitched.

The Moon lifted him through the thick sheets of ice, which crumbled away from his face and clothes in powdery fragments as he emerged from the frozen lake. The boy's chest heaved, and a cloud of breath swirled from his gaping lips as he kept rising through the cold night air. His eyelids pulled apart blearily, as though from a very long, dreamless sleep, and he blinked rapidly against the ice crusted to his dark lashes, and to the corners of his shimmering eyes. They were the color of a clear midday sky, softly mirrored in a fine crystal.

He stared up into the Moon's beaming face. Tenderly as the arms of a mother round a newborn, the light swept away all the fear of waking in darkness, cold and alone, and let him sink gently back down to the earth.

Below his bare feet, along the icy surface his ascent had cracked open, every last scratch sealed itself seamlessly back together. The boy looked down at himself, his slender limbs and torso, the coarse fabric clinging to his freezing skin, without recognition. Every line in his own hands was a question he couldn't answer.

Who am I?

A low, soft voice whispered in his ears.

"Your name," it said, "is Jack Frost."

And the Moon spoke no more.

Hiccup lay awake under his blankets, blinking at the dark. Every swallow felt like a choke in his swollen throat. The child listened to his father's footsteps outside his door, and the faint rattle of his window's wooden shutter from the wind's sharp bellows.

Behind his eyes, he saw it happen again, in scattered pieces that leapt suddenly at him image by random image.

A boy, a friend, was smiling and reaching for him – he held him steady on his little skates – his eyes jerked down with terror – he gasped and pointed out another troll cave – he told him in the lightest voice not to move – something was snapping under his feet – he ran ahead shouting, "Hurry or we'll never catch it!" – he was just looking at him with soft eyes and a silly grin – there was nothing left but a gap in the ice the size of a boy – "You have to believe in me," he said – he was in stitches at his own horrible joke – he screamed –

The child's insides turned. It didn't matter how tightly his arms folded around himself. He still shivered.

He just wanted his mom.

But she wasn't here.

...Or.

"What happens when people can't come back?"

Hiccup lifted his head slightly from his pillow, grief-red eyes growing round as words from the night before came back to him suddenly, like a gentle chime in his head.

"Maybe... they never really leave. Just because you can't see something doesn't mean it isn't really there. And if you believe it's there, Hiccup... it can help you fight your fears, and protect your dreams."

Maybe...

The boy squeezed his eyes shut and strangled the sheets in his fingers.

If he could just... he had to try...

...to believe.

And then he heard it, wafting over the wind like a song in a tempest. It was bright and full, skipping with childlike bursts. It was a laugh, echoing round the sleeping village and all the way up to Hiccup's window.

The boy gasped and threw off his blankets.

He knew that laugh.

Hiccup stumbled to his window and unlatched the shutter, swinging it wide, and leaned from the sill into the night's cold. His mouth fell open, and spread.

A figure in the dark danced through the village streets, laughing and laughing as he ran like his feet were new to him, slipping about and waving his limbs like a gosling trying to fly. The vague shape in the shadows grew evermore distant, but all Hiccup needed was to hear that voice, so easy and so full of life, to recognize the young man who told children the wildest stories, and taught them the silliest games.

The boy giggled softly, holding his sides, and watched until the phantom disappeared into the night.

Jack was right.

No one ever really left.

No one's ever alone.

The one child running the dark and empty streets didn't stop when Jack knelt in front of her. She was probably in a hurry to get home, before anyone noticed she was out so late. He smiled at the little rule-breaker and reached out to catch her before she collided with him.

But his hands couldn't find a grasp, as though her limbs were nothing more than shadows, and she ran on, ran into, ran through him like a blade.

He staggered back, trying to breathe, and felt his chest where she passed right through, not sure anymore that there was anything inside it.

Jack Frost was no more than hollow air to the child, to any child (but one). He could ride the wind like a feather, dust rooftops in powdery white, swirl ice from the tip of his staff against still waters – but he could not be seen, heard, or touched.

Not by people.

There was a shout, then a sea of flames, snapping jaws, and huge reptilian eyes upon scaly hides.

Dragons, the 300-year enemy of Berk, stomped through the village wearing night's shadow, snatching up livestock and incinerating homes. The winged monstrosities sniffed heavily at the air, glared directly at Jack, and snarled.

The newborn spirit just escaped a Deadly Nadder's dripping jowls, rising high and fast with the wind, and he kept flying on until Berk was far behind, and other lands lay ahead.

For ten years, Jack Frost never crossed back into dragon territory. The fire-beings hissed and lunged at the being of ice whenever he drew near. He never set foot back in Berk until word reached him that the dragon war was over, and he could finally return to his birthplace, where a little boy had become a young man...

A/n: Omfg so yeah. Feels. T_T

This one's coming along pretty slowly, just to warn ya... but the basic structure is planned out. ._.

Motivate me with reviews ;)