Warning: I have never read the books; therefore, this is based entirely on what I know from the film and some interpretations from fanfictions I have read.
November
Jamie Bennett had forgotten.
It wasn't a shock, not really, and, to the kid's credit, he did remember for a few years longer than his friends. But high school is rough and draining, for the valedictorians and slackers alike, neither of which Jamie was, in any case. Even the moderate achievers who pass through their school years unremarkably and un-extraordinarily may not realize how quickly they grow up in those four years, but almost everyone does. At the very least, they're forced to stop being kids.
Jamie forgot the other Guardians first, Bunny and Sandy, Tooth and North – though not necessarily in that order – and he hardly even realized it when the stories he told Sophie as she stuck a tooth under her pillow became tall tales and not fun facts.
But for the longest time Jamie could always see Jack Frost, even if, more often than not, he couldn't remember the perpetual kid's name right off. He mistook Jack a couple times for a kid in his geometry class who swung by looking for homework help – why the kid preferred the second story window to the front door he was never quite sure, but the late-night knock on the glass panes felt normal, natural, and so Jamie wasn't too bothered by it.
The most distressing moment for Jack was when he knocked on that window and no one answered.
It was late into the night – Jack had been busy dusting all of southern New England with the first snowfall and a bit of ice, as would be expected for the time of year – and so a knock on Jamie Bennett's window should have been answered by a sleepy kid turned groggy teenager.
Except, on this particular night, it wasn't.
Maybe Jamie really had forgotten now, Jack reasoned, trying to peer in and discern whether there was a sure form giving shape to the crumpled comforter. Jack had been gone for six months, after all. And he'd been so worried leaving this time to go do winter in the southern hemisphere. He'd had a terrible feeling, one that had never really left the deep pit of his gut. Now, it was just migrating back to the shallow end. North told him not to worry, that as a Guardian from the North Pole, he'd keep watch over all the northerners, Jamie Bennett extra included. And besides, North reminded Jack Frost, winter was his responsibility as a Guardian. "All people must be reminded of vhat fun is, Jack. Even you."
But Jack was cursing himself repeatedly as he flew up above Burgess that night. He was looking along all the streets absently, though he wasn't even sure Jamie hadn't been in bed, He was just anxious, the gnawing in his gut growing, because Jamie Bennett had been forgetting him and Jack Frost couldn't bear to think that he had, likewise, forgotten Jamie.
Jack didn't quite understand, yet, that in the great infinity of time, people get forgotten.
December, four years later
Jack shook his head, frost coming off the tips of his slightly-too-long hair and glistening in the moonlight as it fell to the ground below with a whisper.
"No? Whaddya mean, no?" Bunny scolded, looking up at an unmoved Jack. "This is your season, mate. Get on the snowstorms."
"Eh, I don't know," Jack replied. He leaned back, falling around the tree branch by his knees, before straightening his legs and hitting the ground on his feet. In another graceful move, his staff was planted firmly beside him, and he leaned against it, giving Bunny and company a lazy look. "I'm just not - nah, it's more like... it just doesn't feel like winter, kangaroo."
"Doesn't feel like vinter? Jack, Christmas was two days ago. It is very vinter!" North cut in, keeping Bunny, red in the face furious, from jumping Jack Frost.
Jack let out a sigh. "Sorry to break it to you, big man, but Christmas doesn't make it winter. I mean, you've seen those crazy Australians every year, right? They don't need snow to have a jolly old time."
"Ay, watch it! You're on thin ice, mate," Bunny growled. Jack huffed again.
"Been there," he said. "Done that."
The other Guardians fell eerily silent, obviously uncomfortable. Sandy rubbed his neck and, after another few moments, Tooth spoke up.
"Look, Jack, we know that weather is supposed to be unpredictable and all, but maybe just an inch? For us? Or at least, you know, give New England one or two days below 65 Fahrenheit before New Year's Eve? If not for us," Tooth looked away from Jack, "then for Jamie, maybe?"
No one in the intervention dared breath. Bold of her, Bunny thought, eying Tooth with curiously new respect. Not—not that he hadn't respected her before, of course, he hurriedly amended, in case she could read his thoughts with this new gumption of hers. North, as though he could read minds, stifled a nervous grimace.
But Jack just pulled his weight off his staff and shrugged. "I'll see what I can do, but no promises, Tooth."
"That's it? That's all you've got?" Bunny hollered angrily, but Jack ignored him, riding off on the unsettlingly warm wind that had suddenly picked up.
Tooth sighed. Sandy gestured, sand flying – a hearty snowflake, a car, something that might have resembled a Christmas tree topper – but the company shook their heads, no response to what the mute man was saying.
It was going to be a long new year.
Jack Frost did not go far. He was, in reality, just as distraught about the unnaturally warm weather as the other Guardians were. But how was he supposed to explain that it wasn't his fault? At least, not intentionally so.
The wind stilling, Jack dropped down a few feet onto the surface of the lake, the water freezing where he placed his bare feet. He carried his staff on his shoulders, wrists lazily around it, as he wandered in circles. He was thinking, going mad, having already tried and failed a hundred times over to bring on the winter frosts and chaotic blizzards. Was it him? Was there really something wrong with him?
Jack seated himself absentmindedly on the ice. With a hand, he lazily traced the surface of the water, it freezing where he graced it, but slowly, lethargically, like a sleepwalker in a lucid dream.
He was trying to remember his last great snowstorm. Maybe he'd just forgotten how to do it, he thought. He could forget he had a sister, so he could forget how to be a Guardian – that's how it worked, right? He looked up at the moon, who of course had no answers, and he dropped his gaze and he yelled, loudly, with frustration and rage. His anger echoed through the trees, and he felt that sinking feeling in the pit of his stomach. Years, and it had never gone away, not even a bit. In fact, Jack was pretty sure it had gotten bigger, more consuming.
Jack's voice faltered as he ran out of air.
Everything was still for a long, tired heartbeat. Then, closing his eyes, Jack stood. To any on-looking believer, he seemed calm, identifiably cool. But inside, he was seething, like a wolf baring its teeth at its own reflection. It was him, it was his fault. Of course it was. Because that was, and everything since that had been because of him.
Utter uselessness weighing down his legs, Frost swung his arms and threw his staff, resolving that he was, despite everyone's words, not a Guardian. He wasn't; he couldn't be. He wasn't any good at it; there had to be someone, anyone, better. Someone who wouldn't have forgotten, who would have remembered his responsibilities, fun or otherwise. Why did it have to be him?
Landing with a clatter that echoed through the oppressingly empty air, Jack's staff lay whole on the rocks just off shore. He thought about leaving it there, about never picking it up again. About leaving and letting the stupid thing rot away where it lay. But he couldn't.
Defeated, Jack rubbed his hand over his face, before turning to retrieve his staff. A familiar, unforgotten voice stopped him in his steps.
"Still throwing temper tantrums, are we, baby Guardian? Aren't you supposed to be a little too mature for that now?"
Pitch Black was on the bank. Recuperating from his humiliating defeat a decade back, he'd been hibernating restlessly in the darkest corners of a cave high in the Appalachians. If it were up to him, he'd still be there. But it was even harder to sleep than usual with the increased number of fearful cries about global warming in his ears. And so, with an annoyed declaration of, "Since when am I the responsible one?" Pitch had left his cave to see exactly what was the matter.
"You don't seem to be doing your job, Frost, that's what's the matter. I'm allowed to slack, I haven't had a starring role since the Dark Ages - you lot made sure of that - but you, you're playing with the big boys now. You're not allowed to throw fits and keep the skies clear as it suits you."
Jack rolled his eyes. "Are you finished, Pitch? Can I have my staff back?"
Pitch scoffed. "Oh yes, because my Nightmares and I are keeping it from you," he said, gesturing at the empty space and lack of Nightmares around him.
Jack looked expectantly at his staff, where it lay just a few feet from Pitch Black. Then he looked at the too-thin, coal-skinned man perched on the rock in front of him. The man laughed at him. "You think I'm going to retrieve it for you?" Pitch asked. Then he smirked. "Maybe I'll just snap it in two again. I mean, why not? It's not as if you're really using it, in any case."
Pitch stood, and Jack, panicked, took a few rushed steps towards the bank.
"No, wait-" Without warning, the water ceased to freeze underfoot, and with a yelp and an accompanying splash, Jack Frost tumbled into the lake waters below.
Pitch Black, unlike the water, froze. Mouth open, as though he were about to say something, he blinked a couple times, short and quick, before regaining his composure and raising an eyebrow.
"Jack?" he called hesitantly. "Jack Frost? Can you swim, Jack?"
There was, of course, no answer, and Pitch, despite being the bringer of bad dreams, was not exactly sure how to proceed. So, as many do in times of internal identity crisis, he glanced up at the moon. "Well," he said after a moment more, "you sure know how to pick them, don't you?"
But no sooner than Pitch Black had finished this question, a ruckus broke through the water's surface. All of Jack's ice had melted, and so, gasping for air, the kid kicked and paddled and willed himself to the rocky bank. Pitch stared in confusion as one hand and then the other grasped the rock's edge, and the lithe, gasping figure of a brunette boy pulled himself up onto the rocks. Dripping, the boy rolled onto his back and starred at the stars, which reflected brilliantly against the deep brown irises of the kid's half-closed eyes. And Pitch, a pang of loneliness surprising him, picked up Jack's stick, and melted into the shadows.
"Lighten up, North. I mean, it's not like there's a rule that says it has to snow before New Year's Eve. No snow in December isn't unheard of. The mid to late spring temperatures are a bit weird, but hey, the ozone's healing, so we have to keep the humans on their toes somehow." Year placed a mug of warm eggnog beside North's head. Despondent, Santa was hunched over on the bar stool, face-down on the bar top, his arms dangling lamely at his sides.
The toymaker gave a muffled, unclear response to the bartender's half-hearted consolation.
"What's that, North?"
Santa sat up. "I say, not snow on Christmas? Is fine, is fine. Heartbroken children become strong children. But not flurries, even, or, vhat you say, dusting? No frost or icicles or slippery sidevalks? Strong children, yes, but vhat about the adults? Vinter makes adults strong!"
"I'm sure the adults of the northern hemisphere will forgive Jack for some delayed soreness and possible tragedies, North," the bartender replied, grabbing a bottle of Krug 2000 from the shelf along the back wall. He was behind schedule, through no fault of his own, so he supposed he deserved to start off well tonight.
"But is not about Jack, Year, is about duty! Responsibility! Jack is Guardian. Jack is good Guardian."
Bunny snorted from his seat at a table out in the empty lounge. "Good Guardian my—" The champagne popped open and, leaning against the counter, Year refilled his own empty glass.
"Don't you two have anything better to do than bother me? I open in an hour, you know." But the two Guardians ignored him.
"Jack is Guardian. Jack knows how to be Guardian; is like riding bike, or driving sleigh, is impossible to forget how to be Guardian—"
"Yes, yes, you're all heroes." Only Year didn't seem fazed by Pitch Black's sudden arrival. North stiffened, his shoulders broadening as he stood up from the barstool, and Bunny, pulling his boomerang from his back as though he was pulling a sword from its sheathe, readied himself to hop over the lounge seat. "Oh, do relax," Pitch said, a command not at all enforced by the presence of Jack's staff gripped tightly in his hand.
Year did what he did best, cutting through the tension by offering a drink. "Since it's already a party, Pitch, what can I get you?"
"Is not friend, Year," North hissed. Year shrugged.
Pitch feigned offense, before rolling his eyes and replying, "I'm not here for a drink, Year, though I appreciate the acknowledgement."
Year frowned, and took another sip of his champagne. "Why have you come, then?"
"You sorry excuses for protectors can't be bothered to keep track of your allies, so I've had to do it for you," Pitch answered, tossing Jack's staff at North. The wonder-filled man caught it, his face torn between sporting a look of confused suspicion, and enraged blame.
"What did you do to Jack?" Bunny asked. The table behind him rocked as he pushed off it to launch himself over the back of the lounge seat, and the shattering of glass on the marble floor echoed through the tension like molasses in a sideways jar. Year, from behind the bar, let out a displeased grunt.
"Me? Why, I didn't do a thing," Pitch replied innocently. "Something did happen, though," he teased, enjoying himself. It'd been a bit since he'd had to opportunity to dangle something over these twits.
North snapped, moving faster than his appearance may otherwise suggest, and grabbed Pitch by his collar. North slammed the Nightmare King against the bar, knocking over the barstools and earning additional whines from Year.
"Where is Jack, Pitch?" North growled. Pitch Black chuckled.
"Go ask the Man in the Moon." And the boogeyman vanished.