It was cold.

The streets were a slushy mess, the aftermath of the heaviest snow Z-City had seen in years. It was all they were talking about on the news. Most of the reports the night before were speculation about the effect snow would have on public transit. Coverage the next morning was dominated by more of the same. Reporters confirmed the obvious over footage of cars sliding through intersections and colliding, and harassed-looking salarymen at the train station, checking their watches. Even monsters seemed to have been put off by the disagreeable weather, so Saitama was content to stay in the apartment for the morning. They watched the chaos from a distance, since there was nothing they could do about it. Genos made breakfast and Saitama sat with a blanket around his shoulders.

Just after noon, Saitama left for the market, resentful beneath his layers. Even at its peak, the heat of the sun was grudging and not doing much to help matters. He trudged along, hands in his pockets, the lower half of his face obscured by a scarf. Just how cold would it have to be to pose a danger to him? Probably such temperatures didn't even exist. Irritation flared in his chest and he blew it out in a weary sigh, shoved his hands deeper into his pockets.

He dragged his shopping out for perhaps twenty minutes longer than usual, reluctant to leave the warm, dry refuge of the market for the inevitable walk home. By the time he stepped outside again, the wind had picked up and felt like it was whipping right through his clothes. His scarf was much more threadbare than he remembered. It was damp around his mouth, where his breath came out in clouds of fog.

Z-City was even quieter after the meteor; he was surprised to discover it was possible for a place to feel more abandoned. The destruction did not help matters, and it was slower to be cleaned up.

The building was only marginally warmer than outdoors, but it was a relief to return home. Out of the wind whistling in his ears, his footsteps echoed in the stairwell, and he took the last set two at a time.

Warmth spilled into the hall when Saitama opened the door to the apartment, and he edged inside as quickly as he could to keep it from escaping. Genos had done the dishes, the only remaining evidence the lingering smell of soap. He sat at the table with his back to the door, and Saitama didn't have to look to know what he was doing. The clacking of metal fingers moving deftly across a keyboard did not cease when he walked through the door.

"I don't remember it being this cold last year," Saitama grumbled, setting the bags on the counter. He shrugged off his coat and wrinkled his nose in distaste when he realized how much he'd been sweating.

"Actually, sensei," Genos said, "the average daily temperature this month has been two degrees warmer than in the last two years." This statement was delivered with his usual, firm confidence. Saitama had no reason to doubt him. That tone was always backed up by research.

"Huh," he grunted as he hung up his coat.

The crisp sound of typing was finally interrupted when Genos' phone rang in his pocket. He fished it out and spoke briefly to whoever was on the other end. Saitama caught enough of the conversation to guess it was the Association calling. When Genos hung up, he was standing in the doorway, looking into the kitchen.

"A Demon Level threat has been reported at the edge of the city, sensei. Would you care to join me?"

"I'm not going back out in that crap," Saitama said, having already turned his attention to unpacking groceries. "You go on. Have fun."

"I will, sensei!" Genos replied, and Saitama's lips quirked into a smile at his sincere determination. His disciple left, closed the door behind him.

There was no telling how long Genos would be gone, so Saitama returned to his spot at the table, this time with a mug of tea, to read some manga. It wasn't long before boredom crept in. He considered starting the prep work for dinner, then thought better of it. It made more sense to wait until Genos got home. Saitama heaved a sigh and cast his gaze toward his cactus, brought inside from the balcony the night before.

For a moment, he second guessed his decision to stay home.

The manga he was reading didn't require much critical thought, but his focus had already drifted too far away to return to it. The silence in the streets below rose up and seeped into the apartment. It pressed into his ears.

He turned on the TV. Familiar voices - the news anchors he heard every day - filled the apartment. Saitama pulled the blanket tighter around himself.

x

The cold was not deep enough for the snow to endure much longer than a day. Public transit resumed normal operation, and by the end of the week, Z-City returned to its usual gray, winter dullness. Friday dawned cold, but clear.

Genos complained about the timing of the storm in the way he complained about things: by remarking on it in the most offhand way possible. As they ate breakfast, he frowned at the cloudless sky through the window.

"Had the storm occurred a day later, the S Class meeting might have been cancelled."

Saitama shrugged. "You get a free lunch out of it, at least."

In a rare moment of dissent, Genos dismissed this. "My time could be better utilized. The meetings are largely useless."

Seizing on the opportunity to turn this into a teachable moment, Saitama looked into his disciple's eyes, doing his best to affect an air of authority. "Still, you should do your best to get everything out of them you can."

Genos nodded. He set his chopsticks aside to lay his hands on his thighs. "I am attentive, sensei. But not much of importance is said." His gaze dropped to the table, a troubled crease in his brow. "The non-emergency meetings are typically about public relations."

"You should tell them about that broken loudspeaker up the road," Saitama said, tilting his head in the general direction he was referencing. "It wasn't working during the alert testing last month."

Genos glanced toward the wall, as if he could see through it to make note of the location. "I will mention it, sensei. But I believe this section of Z-City is not highly prioritized, being largely abandoned."

"Someone could wander through." Saitama dragged his toast through stray egg yolk on his plate. "And there's that homeless guy who sleeps in the empty convenience store sometimes."

Genos stared at him for a moment, then gave a silent nod. He stood and took his dishes to the kitchen, and when he returned to the table, he took out one of his notebooks. He wrote until it was time for him to leave for the meeting.

x

Monster attacks had also resumed, so while Genos was at his meeting, Saitama went out. He made short work of their neighborhood. Anything of note would have caught Genos' attention, already. Moving in a circle that expanded steadily outward, Saitama covered the populated areas in patches. By the time he reached the edge of the city, he was hungry, so he ate lunch on top of a building, legs dangling over the edge. Soaking up as much sunlight as he could, he gazed out at the skyline.

Had it really been colder the year before? Try as he might, Saitama could not recall. His memory of the previous winter was a colorless blur, cold mornings and dark, early evenings smudged into one another. The only event that stuck out vividly was fighting a monster that sprayed him with water. It drenched him before he got close enough to finish it off. The water left more of an impression than the creature itself - Saitama was freezing by the time he got home. Like an unexpected twinge of nerves, he remembered soaking in the tub with a washcloth draped over his head, breathing in steam. The sound of water dripping from his suit.

Saitama looked down at the people on the sidewalk below. His melancholy sigh was swallowed up by the wind.

x

The most direct route home took him through a neighborhood he did not often visit. It was a quiet patch of small shops and single family homes and had not seen a monster attack for the last couple of years. Saitama only ever passed through.

On a corner, there was a house where a woman leaned out a second storey window, shaking a quilt. A dog ran circles in the yard below, barking up at her. Saitama rounded the corner and stopped when he saw the boy. He was crouched near the front gate, a small figure in a puffy down vest and thick sweater. The kid was probably around six, and wore a knit cap with ear flaps. He was so focused on the cat in front of him, he didn't notice he was being watched.

"Come here, kitty," the little boy murmured.

The cat was fat, gray, and indifferent. It seemed content to sun itself, heedless of the boy and his attempts at persuasion. Placid face turned toward the light, the cat sat on the sidewalk with its eyes closed. It was outside for a change of scenery, not affection.

The boy held out his hand, eyes wide. He whispered to the cat, doing his best to sound gentle and coaxing, though his voice was too young and piping to quite manage the job. It certainly was not convincing enough to tempt a creature who probably spent most of its day napping in the warm darkness beneath a kotatsu.

"Kitty," the boy repeated, wiggling his fingers. A demonstration.

The cat opened its eyes and the boy froze in expectant stillness. With a slow turn of its head, the cat surveyed the street, skipped past the boy as if he did not exist. Bright, yellow eyes fell on Saitama and blinked once, slowly. With a swish of its tail, the cat turned and walked through the gate. Saitama gave a sympathetic groan.

"Ah. Better luck next time," he said.

The boy twisted around, eyes now wide in surprise as he scrambled to his feet. His cheeks were red, embarrassment obvious in the set of his jaw, mouth pinched shut. Saitama had not meant to startle him, and he opened his mouth to say so. Before he could speak, the boy darted past him, around the corner. Saitama turned and watched him shove his hands into his pockets, shoulders hunched.

x

Genos was home and milling around in the kitchen when Saitama walked through the door. Dishes clinked together.

"How was the meeting?" Saitama called as he pulled off his boots.

"As expected, sensei. The Association will send a repair crew for the loudspeaker on Monday."

"Oh. Good." He unclasped his cape and stopped in the kitchen doorway. Genos glanced away from the cupboards, where he was rummaging around for something. When he caught sight of Saitama in his suit, he frowned.

"I was told no attacks had been reported in Z-City today."

"Yeah, I just felt like going out." His nose was still cold and Saitama was unable to tell whether it was running. He sniffed and swiped at it with his gloved index finger. "I didn't see anything," he said, before he made his way toward the bathroom.

His suit was fine for another outing, so he hung it and put on sweatpants and a hoodie. By the time Genos was done in the kitchen, Saitama had taken up his familiar place on the living room floor, reading.

"Sensei."

"Hm?" Saitama looked up from his manga. Genos held a mug in each hand, one extended toward him. He sat up to take it, setting his comic aside.

Tea was what he expected, and Saitama blinked, frowning at the tiny marshmallows floating inside. The smell of chocolate reached his nose in the same moment he realized what it was. It reminded him of coming in from the cold with windblown cheeks as a kid.

Genos seated himself at the table. He raised his own mug to his lips and blew gently on the contents. Saitama tried to imagine him tiny and bundled up. Pink in the face from a snowball fight. Genos cradled his mug in both hands, a fragile piece of ceramic nestled in metal and cables. Saitama didn't realize he was staring until Genos caught him.

"Is everything all right, sensei?"

Saitama dropped his gaze back down to his mug and cleared his throat. He teetered on the edge of an apology, retreated. Apologizing would only draw out the conversation, bring the awkwardness to the surface.

"Yeah. Thanks, Genos," he said.

x

The first thing Saitama registered was that it was colder in the dark.

He fought against consciousness as if dragged there, blinking the haze away with sluggish eyelids. He glared at the ceiling, listening, wondering what woke him. Just as he decided nothing was amiss, Genos sighed. A low whimper was pushed out on his breath, then the sound of blankets rustling as he shifted on his futon.

This was not the first time his restlessness had woken Saitama in the middle of the night. He turned his face toward the figure next to him. Genos was on his side, curled in on himself, his blanket pulled up to his chin. Only his face was partially visible, burrowed into his pillow.

He might start talking soon. It had happened before.

"Oi. Genos," Saitama's voice was rough from sleep. He looked up at the ceiling again and rubbed his eyes, waiting for a response. When none came, he repeated himself. "Genos," he said, a little louder.

The flicker of Genos blinking away sleep preceded the steady glow of his eyes, open in the darkness.

"Do you hear something?" Saitama asked. There was a moment of silence.

"No, sensei." Genos mumbled, sounding a bit groggy despite whatever analysis he was doing. "I detect no disturbances."

"Mm." Saitama stared at nothing, at shadows. Neither of them spoke. He could tell Genos was watching him. The ceiling was still dark, all of the light from his eyes on Saitama. Outside, the wind whistled around the building.

"Are you cold?" Saitama asked.

The answer was automatic, technical information he had probably been given before, and forgotten. "My systems automatically adjust my body temperature to maintain homeostasis."

Saitama thought of the time he heard Genos groan someone's name in the darkness, and how helpless he sounded. It was not a name Saitama recognized, and he never asked about it. Genos sounded lost, that night in his sleep. Was he even capable of getting lost? Homeostasis . When was the last time he felt cold? When Kuseno found him, maybe. He never asked Genos about that , either. What time of year it was, if he had school, or remembered what he had for breakfast that day.

It was cool in the apartment but Saitama was sweating, nervous without knowing why.

Genos sounded more alert when he asked, "Are you, sensei? Cold?"

Saitama sighed. "A little," he admitted.

"If you would like to move closer, sensei," Genos murmured, his voice soft, "you might be warmer."

He turned onto his side. Genos watched him, only silence between them. The blackness of his eyes was less obvious in the dark, skin amber under the glow of his irises. He lifted his blanket in offering. The silver tips of his fingers poked out, lit from below, by the light of his core. Heat radiated through the vents on his chest.

After a tense moment of hesitation, Saitama scooted closer to the edge of his futon. Genos moved closer, too, extending his arm with careful slowness. He tugged his blanket over so they could share it, then withdrew his hand, tucking it against his body. Warmth settled through Saitama's stiff shoulders and he relaxed into it with a grateful sigh.

If it was warmer in his apartment this year, it was because Genos was there.

"You're the best, Genos."

"Thank you, sensei."