Ships were much better than trains, Gon decided early on.

He had never been the biggest fan of trains. They were stifling and boring. This train in particular was humid with the press of hot bodies, which far overpowered the one or two cracked windows that attempted to aerate the cars. There was also a distinct lack of Killua, who had made the trips on the railways bearable in the past - they at least had known how to make each other laugh to fill the time.

Gon missed Killua terribly, and he also missed the open air of the ocean and climbable masts and endless buffets.

Trains did not have buffets, which Gon had known objectively, but the knowledge hadn't spared him the twinge in his stomach when he went to the dining car and they told him that ordering extra meals would be costly.

Which meant that Gon's only sources of entertainment were to stare out of the window - which he had tired of ages ago - or… Hisoka.

The magician in question was sitting cross-legged and humming contentedly to himself as he stacked cards on cards, either oblivious to or dismissive of Gon's plight. Gon watched him for a time, feeling the familiar itch of restlessness slither beneath his skin, and it wasn't long until Hisoka's meticulous process grew similarly uninteresting. He considered getting up and pacing.

"Practice your meditation," Hisoka suggested abruptly, startling Gon.

An upwards flicker of his yellow eyes was all that alerted Gon to the idea that Hisoka had been paying attention to him all along, and by then the magician had already busied himself again.

Gon was doubtful that meditating would do him any good when he had no Nen to speak of. He wasn't even sure if he could allow himself to sit still for long enough to fall into a meditative state - but he hardly had any other options, what with the only other thing available being… His eyes strayed toward his backpack, which lay discarded nearby, and thought about the paperwork that lay within. He shuddered.

Gon lifted his legs so that he also sat criss-cross, wriggling in his seat until he was passably comfortable. Breathe in, breathe out. He let the summer humidity make his mind numb, and closed his eyes.

When he opened them, Hisoka was gone, and he was left alone in the too-small car. Despite having one less person to fill the space, the walls seemed just as oppressively close as they did before. The flooring rattled as the train passed over a rough patch in the tracks. A thin layer of sweat clung to his skin, and the warm cloying air made it impossible for it to evaporate, which only served to amplify his discomfort. He thought that if boredom could be made physical, this is what it would feel like: sticky skin, in an enclosed space just this side of too hot.

He wasn't sure how late it was, but a cursory glance out of the window told him that not much time had even passed; from the position of the blazing sun it had been perhaps only a couple of hours. He groaned, throwing himself back; his head hit the wall with a dull thud. He could feel the vibrations jittering up through the wall and into his skull, and the weird buzzing of it was maybe the most entertaining thing to happen to him in forever, until it got overwhelming and he had to lift himself away.

He stood and paced as well as he could one or two or three times, then flung the door open after determining that walking up and down the entire train would be at least more entertaining.

The awful creaking groan of metal on metal sounded above him. Instinctively he tensed, readying himself for a fight - or flight - and as he turned he watched the hatch in the roof open slowly outward to reveal the blue, blue sky.

There was a blur of cherry red and candied pink and then Hisoka was there, craning his neck through the hatch to peer at Gon.

Upside-down. On the top of the moving train.

"Gon," the magician greeted casually, as if he wasn't upside-down on a moving train. His eyes were half-lidded and his lips upturned, looking awfully pleased with himself.

"Uh," Gon said, almost letting himself relax. "What'cha doing up there?" He didn't close the car door.

"You're bored, aren't you?" Hisoka asked instead, clambering farther into their shared compartment, spidery and somewhat unsettling in his movement. He had to be using Bungee Gum to do that. "Come up here with me and I'll show you."

This felt like a bad idea. With Hisoka involved, it had to be. But getting on top of a train in motion - and staying up there - sounded like a challenge that Gon could meet. It sounded a little like fun, actually. And he was so very bored and unchallenged. He eased the door closed.

"Okay," he said.

He kind of regretted it when Hisoka looked even more pleased with himself, his smile curling up into a cheshire grin. "Get up here, then," Hisoka invited, and then disappeared back through the hatch.

Gon was left to figure out his own way up. He couldn't have really expected any less of the magician. Fine, then. That was doable.

He looked around the car for something he could climb. Most of the furniture was in some way bolted to the floor, which meant that he couldn't move anything to a better place. He shifted his gaze to the bunk beds - if he climbed up and positioned himself right, he should be able to reach the hatch.

He hefted himself to the top bed and tried to stand, his toes to the edge, his head and shoulders hunched to avoid hitting the ceiling. He swung his arms out a few times, gauging the distance and warming his muscles, and then jumped.

His fingers just barely caught the edge of the hatch, and he scrabbled at it for a moment before he was able to find his balance again. Feeling the slightest strain in his upper arms, he hauled himself to the top of the train.

He was almost immediately shoved back through the hatch by the buffeting winds. They tore at his skin, pricking his face like hundreds of needle points, and he screwed his eyes shut, tears leaking at the corners. He crouched low to the roof of the train, bracing himself against the high velocities.

"You made it," Gon heard Hisoka praise.

He peeled his eyes open, squinting, to see Hisoka standing before him, nonchalantly picking at his sharp nails. With a small grunt of effort, Gon stood, inching away from the hatch opening so he didn't get thrown back into the car.

"Why are we up here?" Gon shouted above the wind, his skin going numb as he slowly acclimatized to train-top conditions.

"Training," Hisoka answered blithely, making his voice somehow audible even though he wasn't yelling.

Gon's face must have betrayed his confusion, because Hisoka continued, "Until you regain your Nen, you need to know how to defend yourself without it. You already have some skill in hand-to-hand combat, true, but you lack finesse, and any real enemy worth their salt could take you down."

Gon blinked and rubbed away more of the tears that vainly tried to moisten his eyes.

"So we're going to start sparring," Hisoka finished grandly.

"Up here?" Gon asked.

"Where else?"

"Good point," Gon conceded, still fighting against the wind.

"Besides," Hisoka said, "we're hardly about to start off easy."

"That's fair." Gon slid one leg behind him and settled on his haunches in his customary fighting stance.

"Gon," Hisoka advised, ready in his own familiar, fairly languid posture. "If there are openings, take them - if there are none, make them."

Gon only acknowledged Hisoka by darting forward, struggling to move swiftly against the flow of the wind. Hisoka had the advantage of the wind at his back; he blocked Gon easily, upsetting Gon's balance and following through with a blow to the sternum that knocked the air from Gon's lungs.

In the second that Gon allowed himself to recover, he looked Hisoka over. The magician was favoring his left side - whether unintentionally or not; if Gon could just feint, he could make it around to the other side and have the wind's advantage.

Gon was immediately and unpleasantly reminded of their Heavens Arena showdown - only this time, he had neither the space nor the power to perform the same dazzling, distracting tactics. It didn't sit well with him.

Hisoka was good at waiting patiently for Gon to make the next move, entirely confident in the idea that he would be able to counter whatever Gon threw at him, and that it would take more than one punch for Gon to realize any particular method of attack. Gon dipped and rolled to the side, narrowly avoiding the reach of Hisoka's claws; with more strength than he thought he had, he jumped back up adjacent to Hisoka's left side and landed a punch, as grazing as it was.

A hand was reaching out towards Gon's face before he could even blink, and something about Hisoka's proximity made Gon's blood thunder in his ears; his heart pounded hard against his ribs, making him dizzy, threatening to break free. His teeth were set on edge. This was Hisoka's bloodlust, rippling along his skin and leaving goosebumps. Gon grit his jaw, and with effort he made himself duck, almost tripping up with the wind and the clatter of the train. Sharply clawed fingers just missed slicing at his eyes.

Breath came short, but it came, and Gon balled his fists, more frustrated than scared. He thought about his fishing rod, still in his backpack - but no, that was the point, Hisoka said hand-to-hand - but how was this supposed to help him with his finesse when this was just a struggle to keep up -?

"Focus, Gon," Hisoka coaxed, taking just the slightest step back to give Gon the chance to shake himself into concentration. "Finesse doesn't mean you can't play dirty," he added, as if he'd read Gon's mind. "It means survival. It means precision. You've spent so long teaching yourself to be a bludgeon - now teach yourself how to be an arrow. Or a lure on a fishing pole, if you'd like."

Gon could still feel the crackle of his bloodlust, like lightning that lingered in the clouds before it struck, but Hisoka must have reigned it in - it no longer crawled up his forearms, and it was easier for Gon to think about fighting.

An arrow. A lure. Back to when he had to rely only on being nimble. He thought about the King of the Swamp and dazzlingly pink worms. He thought about Hisoka's cards, and about Killua and the Zoldycks, and he wasn't quite sure that style was very… him, but he couldn't deny that finesse was its own kind of powerful.

Hisoka didn't give him much time to think on it. The magician struck first this time, moving with inhuman speed toward him. Acting on instinct, Gon ducked low, crouching close to the train roof with one leg outstretched; he kicked out at Hisoka's heels, and nearly caught him before Hisoka leapt away. The latter spun quickly and landed a blow to Gon's gut with his knee, winding the boy and claiming the advantage with a grin.

"Lighter on your toes, Gon," he admonished.

Staggering, Gon just managed to dodge Hisoka's next jab. He furrowed his brow. Hisoka was focusing his attacks on compensating for Gon's smaller stature, meaning that with the kicks and lower arm movements, he was leaving his upper body less protected…

Thinking of how Killua moved, Gon weaved between Hisoka's limbs and jumped, aiming a precise uppercutting punch to his jaw.

Hisoka brought up his arms, using one to bat Gon away and the other to roughly shove him back by the solar plexus. "Very good, Gon," he commended even as he did so. "On anyone with less experience, that probably would have been a hit," he added, managing to sound both impressed and self-important.

Gon landed hard, one of his knees bowing beneath him and forcing him to throw out his hands to keep himself from face-planting. His chest ached, both from the blow and the churning emotions that threatened to boil over. Habitually he tugged at the place where his Nen should be, and faltered when, despite the anger and frustration and hurt and fear, he still felt nothing. It was so wrong, when he could sense Hisoka's bloodlust but couldn't even open up his nodes enough to see it.

He had to be better. He had to be better. He stared at Hisoka, and tried to think past the bile that burned in his throat.

"That look," Hisoka moaned, bringing his knee forward to rail at Gon again. "There's the fire I've wanted to see… Yes, Gon -"

Don't tense up, he begged his muscles. Don't tense up…

He waited until Hisoka's strike was too close to finding its mark for the magician to change course, and then Gon gathered all of his remaining strength to roll to the side. Hisoka's balance would be upset, and he left his right side a bit open, and - Gon tried to sort through everything Killua ever told him about anatomy - if he jabbed right there -

He darted forward, ignoring the discomfort and the protests deep in his bones, and dug his fingers into where Hisoka's kidney - theoretically - should have been. He let out a wheeze he didn't realize he'd been holding in.

Hisoka froze in place, his lips unfurling as he smiled so broadly that his face paint cracked. "Excellent, Gon," he said breathily, and stood there a moment even after Gon broke contact, as if he was taking the time to savor it. Like those overrated wine tasters Gon had seen in marketplaces.

Gon backed away, shaking out the tension from his limbs, forcing his muscles to obey even when all he wanted to do was lay down.

Hisoka appeared to be back to his ordinary self - whatever that meant by Hisoka's standards - by the time he'd finished psyching himself back up.

"Again," the magician demanded.

It seemed that that had been the only time Gon would get lucky that day.

Hisoka's barriers were up for real now, and among the flurry of punches and kicks and dips it was impossible to find another weak spot. Above them, the sky melted from a bright blue to a dark blue, then to a hazy orange as the sun dipped low. The chill of the winds grew even sharper.

Gon's arms shook from exertion, but he could still get back up. He wasn't about to quit if he could help it.

Hisoka's knee connected with Gon's abdomen again in a moment of heedlessness, and Gon fell, his already-frozen fingers hitting the icy metal hard. He dry-heaved, then struggled back to his feet, swaying in the strong winds. He wiped his mouth on his sleeve even though only spittle had come out.

"That's enough," Hisoka said, and stood normally.

"What? No! I can keep going -"

"That's enough, Gon. Your recklessness is exciting, truly, but I'm not about to let you hurt yourself irreparably." Hisoka walked close and laid a spindly hand on Gon's hair, which was stiff with dried sweat. "We're done for today. You've already improved more than I expected - you continue to amaze me, hm, Gon?"

Gon forced himself to stand upright, muscles rigid, and clenched his fist. "But - it's fine, I can still…" He lurched.

"Gon!"

He passed out cold before he even hit the train roof.

He awoke encased in warmth, and once he regained his ability to think he immediately thought that this what babies in their swaddles felt like all the time, which wasn't so bad. Until he wriggled in his swath of heat, only to find that he couldn't move very much at all. He blinked the bleariness from his eyes to observe his surroundings.

He was in… the train car. He was most decidedly in bed too, and looking down he realized that not only was he covered in blankets - he was completely rolled up in them. But the sheets were fairly thin, and it felt like there was an additional weight surrounding him as well that even more decidedly pinned him down.

An odd rustling of papers drew his attention to their small side table, where Hisoka sat - rifling through his backpack. He vaguely remembered overexerting himself, but nothing in his recent memory could justify what Hisoka was occupying himself with.

Gon tried to say something, but didn't quite manage to open his mouth all the way, so all he made was a weird sound.

"Ah, you're awake," Hisoka remarked, looking over at him, and not even trying to be subtle about going through Gon's belongings. "Are you enjoying the warmth?"

"Uh," said Gon.

"I used Bungee Gum as the final layer," Hisoka continued, as though Gon has asked. "Seeing as it has the properties of both rubber and gum, it stuck to the other blankets very nicely while adding additional insulation. It's also rigid enough that you won't be moving anywhere - wouldn't want you to hurt yourself in your sleep, of course." It was obvious that he was very proud of this.

"Thanks," Gon said, unimpressed but genuinely touched by the sentiment. "D'you think you could let me go now though?"

"I thought you'd appreciate being a Gon Burrito," Hisoka commented, but released his Nen. He let Gon work himself free from his blanket wrappings.

"...I'm on the bottom bunk," Gon observed flatly once he could at least sit up, fighting back a wince at the strain in his muscles.

"Yes?"

"But we never even decided…"

"Gon, I staked my claim on the top bunk. I always get the top bunk. That's just how it is."

"I'll beat you in Rock, Paper, Scissors for it."

"...Nah," Hisoka concluded, then continued flicking through Gon's paperwork. "By the way, Gon," he said, waving Gon's maths homework before him. "What's all this?"

"...Homework that Mito gave me,"Gon admitted quietly.

"But it's not done," Hisoka felt it necessary to point out, quizzically.

"Nope…"

"But if you were so bored…"

Gon threw his head back, groaning. "Because I'm not good at math and I don't like doing it." What weirdo liked doing math?

Hisoka was silent for a while as he scanned the pages. "This is simple enough," he said eventually. "Because of my profession, I had to teach myself to do calculus mentally." Of course he did. "It's essential, not just to keep up with card sharks but to moderate one's Nen properly -"

"Hisokaaaaaaa," Gon whined.

There was a speechless pause as Hisoka visibly weighed his words on his tongue. "I'm saying -" He flicked at his dangly earring. "I can help you."

"Can we please go back to sparring," Gon deadpanned.

"Definitely not," Hisoka admonished. "But since you're awake anyway -"

"I'm tired."

"I can see you bouncing your foot up and down."

"Can we eat first?" Gon's stomach rumbled in a timely manner, for extra emphasis.

"Fine. But when we get back…" Hisoka got a wicked gleam in his yellow eyes that Gon definitely didn't like. It wasn't quite bloodlust, but for something as passive as mathematics… it was pretty close. Gon shuddered.

It was odd, but after Hisoka dragged him through his times tables for the fifth time, and gave detailed explanations on all the mental shortcuts he could take to find products or quotients, Gon felt a bit more confident in his mathematical skills. Which - they still weren't great, but it was an improvement, and together they powered through the first couple of pages of his homework.

He was certainly not going to feel grateful to Hisoka for forcing him to do math - not right now, anyway - but Hisoka really did make it… easier.

"Like this, see?" Hisoka demonstrated, marking the paper with a pencil stamped with the locomotive company's logo.

"Where did you get that number."

"From in front of the variable. They're attached by the invisible multiplication sign, so you have to divide both sides - Here, do a similar problem."

The magician sometimes used his cards to better explain numerical values and properties, and maybe it was having something physical to attribute these arbitrary numbers to, but Gon was starting to get an inkling as to how Hisoka performed mental math daily.

"This will help, when you get your Nen back," Hisoka reminded him when he grew weary of sums. "It's the key to calculating how much aura you should be emitting, and where."

Feeling exhausted down to his soul, Gon yawned cavernously, and the magician-turned-sensei finally deigned it time to put the paperwork away. "We'll continue this tomorrow," he said.

"Ugh," was all Gon had to say to that before flopping back onto the bed.

He was awake only long enough to recognize that Hisoka had begun yet another card tower, and then he drifted off.