Premise: Mitsuo Suwa wakes in his teenage body at 18 and discovers he's been given the Perman set again — but with one twist: he remembers the anime and everything that happened there. That meta-knowledge gives him an edge, but also the heavy weight of knowing what could happen.
Setting: Modern Japan, slightly older-feeling version of the Perman world (high school students, grudgingly responsible adults, secret-hero networks). Birdman's secret society still exists; the Perman system has rules — masks, belts, and the moral code — but Birdman experiments with an upgraded gadget (the "Echo Mask") that amplifies emotions into subtle power shifts.
Cheat/Ability: Mitsuo's main advantage is memory + soft precognition — not absolute invulnerability or perfect foresight, but split-second déjà vu that hints at likely outcomes (enough to change choices). He also gets a slight upgrade to his Perman kit: the Echo Mask, which resonates with his emotions, making his strength/flight subtly stronger when his motive is protective or when his heart is focused on someone he cares about.
Romance rules: Mature relationships, flirting, tension, deep emotional honesty. No explicit sexual description. Consensual interactions only. All characters involved are 18+ in this AU.
Stakes: Mitsuo must decide whether to use his knowledge to protect people he remembers (and maybe change them), or to explore his own desires — including a dangerous new intimacy with someone who may also understand the soul of a hero.
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Chapter 1 — "Second Life, Same Smile"
Mitsuo opened his eyes to morning light that felt both new and painfully familiar — the thin, honeyed sun of late spring, the way it slid across the tatami and caught at dust motes like drifting stars. He blinked and for a second the room was the cramped one from his favorite childhood memories, then it was the one he'd fallen asleep in last night: his new-18-year-old body, his school uniform folded on the chair, a Perman mask tucked into the drawer like a fossil waiting to be reanimated.
He laughed before he could stop himself — a stunned, small noise that had nothing heroic about it. "Again?" he breathed. The memory of waking up in his childhood bed when he was a kid and meeting Birdman for the first time was a patchwork now; this time the seams were more obvious. He remembered episodes, arcs, the faces of people he'd loved on a screen — the original show he'd binged until the phrases stuck in his head. He also remembered what it had felt like to be a viewer who wanted more than the show had given him: closeness, choices, tenderness they'd never let linger on camera.
On the bedside table lay a plain white envelope. His name — Mitsuo Suwa — was on it, hand-scrawled in an unsteady script he couldn't place. He sat up, heart tipping over with a warmth that had nothing to do with the sun. The echo in his chest — the memory-precognition he'd woken with — hummed like a distant bell. Small images flickered: a classroom, a laugh, the weight of a glove in his hand, a soft hand tucked into his own.
He unfolded the letter.
"Returnee," it began, and his grin went crooked. Birdman's elliptical, theatrical signature was at the bottom, as if the man himself had stepped out of the pages he loved. The letter asked for one thing: meet in the old observatory tonight at eight. Bring the mask. Do not tell anyone.
Mitsuo slid his fingers along the drawer until his skin brushed the cool plastic of the Perman mask. It surprised him — the way it felt real, as if it had been waiting. He had watched the show enough that the ritual of donning it felt like returning to a dance step, and yet the knowledge of what came after made his fingers tremble. In the anime, being Perman meant fights, slapstick, and the sacred rules. In his mind, it had always been cleaner: heroism in straw-hat proportion. Now, with a body that counted years differently and a memory that tasted like regret, it tasted like possibility.
School that day moved around him in a blur of textbook pages and a thousand polite smiles. He noticed details he hadn't noticed as a viewer: the crease at the corner of a classmate's mouth when she hid a laugh, the exact tilt of the gym teacher's jaw when he suspected someone had skipped training, the way the bell slid like a metronome toward the moment school would end and the world would open.
He met her by accident — or by small, tidy fate. Izumi Takahashi stood beneath the cherry tree, the petals making a soft confetti around her, and for a breath Mitsuo understood why writers loved that kind of scene. She had a book tucked under one arm and a thermos in the other, and when she smiled it was like someone turning up the light in a familiar room. She was not a character from the anime he remembered; she was new, but her face pulled at something that felt like a script he'd read before. Maybe it was her eyes — steady, curious — or the way she pushed a strand of hair back and laughed at something small.
"Hey, Mitsuo!" she said, and the sound fit him like a favorite uniform. He'd been Mitsuo for years on screen and in memory, but being him with this knowledge was different. He felt like a man who'd been handed the map after already knowing a hundred traps, and Izumi's presence rearranged the routes until every line pointed to her.
"Hey," he answered, too plainly. "You okay? You look… spring-like."
She rolled her eyes, but not unkindly. "Is that your new line? You've been weird today." She leaned closer, conspiratorial. "You're quiet. Did you forget how to be annoying?"
He laughed. The sound was a promise — an opening. Between them the air seemed to hold a note of possibility, nothing explicit, just the slow turning of a key.
Evening came with more shadow than he'd expected. The observatory was an old, circular building that smelled like dust and rain, and Birdman's silhouette was smaller than a man and larger than an idea. The man who called himself Birdman smiled with the same careful weirdness the letter had hinted at.
"You remembered," Birdman said, as if surprised himself.
Mitsuo held out the mask like a lit candle. "Why give it to me again? I remember how it goes — the rules, the danger. I know the show. I know the fights."
Birdman's eyes — bright, too-bright for a man of habit — softened. "You remember the script, not the life between the lines." He tapped the Echo Mask, which gleamed faintly under the observatory light. "This time, I wanted someone who had nostalgia enough to feel mercy, and enough newness to write differently. You will have what you had. But your heart will change how it works."
It felt like a dare. It felt like a blessing. When he slid the mask over his face, the world sharpened into a focus he'd always loved about being a hero: the sense of weightlessness, then the small, electric roar of the first flight. But the Echo Mask was different. A current of warmth tickled the base of his skull and, impossibly, he heard Izumi's laugh threading through his memory-echo like a pulse.
Afterwards, alone atop the observatory, Mitsuo tested the edge of his knowledge. The precognitive bell chimed once: he saw a future minute — Izumi tripping on a loose tile, a hand catching her arm. Reflex moved him; he veered mid-flight without thought and steadied her, heart punching through his ribs like a fist.
She looked up at him, wind in her hair, a pastel smear of adrenaline across her cheeks. "You okay?" he asked, breathless.
"I'm fine now." Her fingers brushed his as she pushed a fallen strand of hair behind her ear. The contact was small, ordinary. The newness of adult skin, the simple politics of touch — he'd watched versions of this as a viewer, but standing on the threshold made it real and sharp. He felt the Echo Mask's warmth answer, a subtle tightening, as if approving.
"Thanks," she said, and there was a question in the word, an invitation.
Mitsuo's memory whispered warnings — the villains he'd seen on screen, the times he'd watched friends get hurt — but the bell's faint future-flash suggested small divergences, openings where tenderness might reroute catastrophe. In the hush between breaths, he realized what he wanted most: not to re-enact a script, but to rewrite the scenes where they'd all been boxed into neat endings. He wanted to protect Izumi, of course — but he wanted to know her wildness, her hunger for late-night ramen and the ridiculous novels she loved; he wanted moments that wouldn't have fit on Saturday morning television.
He landed, and the observatory hummed with stillness. "I remember the show," he said finally, honest. "But I don't want to be trapped by it."
Izumi's smile was a slant of moonlight. "Good. Be boring, be reckless, be the hero who can be soft. I'll keep you honest."
Birdman watched them with eyes like a doe and a hawk. "Then go," he said. "Begin."
Mitsuo thought of the faces from the anime — the laughter, the scrapes, the small kindnesses. He thought of the weight of knowing and the danger of using it as armor. And when Izumi's hand found his again, steady and warm, he smiled the way someone smiles when they decide to write their own ending.
Outside, the city lights unfurled like a promise. The bell in his chest chimed, not a warning now but a metronome. He had knowledge, and he had time. He had a mask that answered his heart. For the first time, being Mitsuo felt like a beginning he could choose.