The hospital room smelled like antiseptic and the faint, familiar musk of Katsuki's skin—that hay-and-woodsmoke scent that had become home to Izuku, now diluted by bleach and the hum of machines. Izuku sat in the hard plastic chair by the bed, his hand wrapped around Katsuki's, feeling the bones too close to the surface, the pulse too weak beneath his thumb. His belly had grown in the month since that phone call—a round, hard swell pressing against the fabric of his hoodie, a constant reminder of why he was fighting so hard to keep this man alive.
Katsuki's chest rose and fell with a shallow rhythm, the oxygen cannula taped under his nose, his eyes closed more often than open now. When they did open, those crimson irises found Izuku first, every time, like he was checking that he was still there. "You gotta eat somethin'," Katsuki rasped, his voice a dry scrape. "You been here three days."
"I ate." Izuku's lie came automatic, his thumb tracing circles on the back of Katsuki's hand. "The cafeteria had soup."
"Bullshit." Katsuki's fingers twitched, a weak squeeze. "I can see your ribs from here. You're carryin' my kid. You need to—" A coughing fit rattled through his chest, and Izuku leaned forward, his free hand hovering over the call button, but Katsuki waved him off with a shaking arm. "I'm fine. Don't you dare call that nurse."
Izuku's eyes burned. He hadn't slept more than an hour at a stretch, and each time he closed his eyes, he saw Katsuki collapsing in the barn—saw the way his grandfather's hand had clutched his chest, the way his face had gone gray before the ambulance came. "I'm not leaving you," Izuku said, his voice cracking on the last word. "Don't ask me to."
Katsuki's hand moved, dragging Izuku's palm to his chest, pressing it flat over the thin hospital gown where his heart beat a weak, erratic rhythm. "Feel that?" he whispered. "That's been goin' for sixty-five years. And every second of it, I was waitin' for somethin'. I didn't know what. Then you showed up." A tear slipped from the corner of his eye, tracking down the weathered groove beside his nose. "Four months. That's all I got. And it was worth every year that came before."
Izuku broke. He let himself fall forward, his forehead pressing into Katsuki's shoulder, his tears soaking the thin fabric. A sob tore out of him, raw and animal, the sound of a boy who had finally found his home only to watch it crumble. "It's not fair," he choked. "I just found you. The baby's not even here yet. You promised you'd fight."
"I am fightin'," Katsuki said, his voice thick with his own tears. His arm came up, weak but true, wrapping around Izuku's head, holding him close. "But sometimes... sometimes the body don't listen to the heart. Not the old, tired one. The one that loves you." He pressed a kiss to Izuku's hair, his lips dry and trembling. "I'm sorry, baby boy. I'm so damn sorry."
Izuku felt the words break something in his chest. He cried harder, his hand splaying over Katsuki's heart, feeling it stutter beneath his palm. "I can't do this without you," he whispered into the fabric. "I don't know how."
"You can," Katsuki said, his voice dropping to a strained, fierce whisper. "You got Eijiro. You got his brother. You got the farm—it's yours now, all of it. And you got that little one." His hand found Izuku's belly, palm flat and warm, cradling the swell through the hoodie. "You tell 'em about me. Tell 'em their old man was a grumpy bastard who loved their mother more than he ever thought he could love anything."
Izuku lifted his head, his face a mess of tears and snot, his green eyes red-rimmed and swollen. "You're not dying," he said, the words fierce and desperate. "You're not. I won't let you."
Katsuki smiled—a small, tired, heartbreaking thing. "You can't stop the tide, baby boy. But you can damn sure ride it 'til the last wave." He squeezed Izuku's hand, his thumb brushing over the knuckles. "I love you. I ain't said it enough. I love you more than I ever loved anyone, and that includes myself."
"Papa—" Izuku's voice broke on the word, the name he'd claimed as his own, the name that meant everything in this sterile room.
"I know." Katsuki's eyes fluttered closed, his hand heavy on Izuku's belly. "I know. Just stay with me. That's all I need."
Izuku lowered his head again, pressing his cheek to Katsuki's chest, listening to the heart that had given him everything. The monitor beeped its steady, fragile rhythm, and outside the window, the first leaves of the season began to fall.
Izuku's cheek was still pressed to Katsuki's chest when the air changed just outside their hospital room. His exhausted brain took a full second to register it—the rhythm shifting, a hurried commotion happening. He jerked upright, his hand still splayed over Katsuki's heart, and saw the nurse burst through the door, her face lit with something he couldn't name.
"There's a match," she said, breathless. "A heart. They just called it in—twenty minutes out by helicopter. We need to move."
Izuku's mouth opened. Nothing came out. He looked down at Katsuki, whose crimson eyes had cracked open, glassy and confused, and then back at the nurse, and the word finally broke free. "What?"
"A donor heart," she repeated, already pressing buttons, pulling the bed brakes. "Someone's family said yes. We've got a surgical team standing by."
Katsuki's hand found Izuku's wrist, grip weak but real. "Baby boy—" His voice cracked, raw and disbelieving.
"I'm here." Izuku was crying again, but different this time—wet, messy, relieved sobs that made his whole body shake. "I'm here, Papa. You're gonna be okay. You're gonna—" He couldn't finish. He pressed his forehead to Katsuki's, felt the older man's breath hot and uneven against his skin. "I love you. I love you so much."
Katsuki's hand came up, trembling, and cupped Izuku's jaw. "I love you too," he rasped, and then, with the nurse already unlocking the bed's wheels, he pulled Izuku down and kissed him. It wasn't gentle—it was desperate, urgent, the kiss of a man who might not get another chance. He tasted like hospital air and tears, and Izuku clung to him like he could anchor him to this world through sheer want. The nurse said nothing, just turned her back and gave them the moment.
They were pulling Katsuki through the double doors when Izuku caught Eijiro's voice behind him—he and Tetsutetsu must have run the whole way, their boots squeaking on the linoleum. "Is it true?" Eijiro gasped, and Izuku could only nod, his eyes locked on the gurney disappearing into the operating wing. Katsuki's hand rose, a weak wave, before the doors swung shut. Izuku stood there, his chest heaving, his hand pressed to his belly where the baby shifted, and let himself believe.
The waiting room chairs were plastic and unforgiving. Izuku sat between Eijiro and Tetsutetsu, their shoulders bracketing him, a wall of warmth in the sterile cold. Eijiro's hand found his and squeezed, rough calluses against shaking fingers. Tetsutetsu sat on his other side, silent and solid, occasionally reaching over to rub Izuku's back in slow, grounding circles. Hours passed. The clock on the wall ticked past midnight, then one, then two. Izuku didn't sleep—couldn't sleep—his eyes fixed on the doors, his mind running through every possible outcome, every prayer he'd never learned to pray.
When the surgeon finally emerged, her scrubs wrinkled, her mask pulled down, Izuku was on his feet before she could speak, his heart lodged somewhere in his throat. She smiled. "He's doing well. The heart is beating strong. We'll keep him sedated for a few hours, but he's stable."
Izuku's knees buckled. Eijiro caught him, hauling him upright, and Izuku buried his face in the other man's shoulder and sobbed—ugly, desperate, grateful sounds that echoed off the waiting room walls. Tetsutetsu let out a low, shaky breath and slumped back into his chair, his head falling back, a grin splitting his face.
They let Izuku into the recovery room just before dawn. Katsuki lay in the bed, tubes and wires everywhere, his chest rising and falling with a rhythm that wasn't fragile anymore—steady, strong, true. Izuku kicked off his shoes, climbed carefully onto the narrow mattress, and pressed himself against Katsuki's side, his ear over the new heart, listening. Lub-dub. Lub-dub. A sound he'd thought he'd never hear again. He draped his arm across Katsuki's chest, his hand finding the warm skin above the bandages, and let the exhaustion finally pull him under.
Katsuki woke to sunlight and the weight of Izuku's body tucked against his side. His chest ached—a deep, surgical throb—but his lungs filled with air that didn't burn, and his heart beat in a rhythm that felt like a second chance. He looked down at the mess of green curls pressed into his shoulder, at the hand splayed over his heart, at the small swell pressing against his hip, and felt something crack open in his chest that had nothing to do with the incision. His arm came up, heavy and slow, and wrapped around Izuku's shoulders, pulling him closer. "Hey, baby boy," he whispered, his voice a dry rasp. "Mornin'."
Izuku stirred, his eyes blinking open, unfocused and red-rimmed. He looked up at Katsuki's face, at the color in his cheeks, the light in his crimson eyes, and a sound escaped him—half laugh, half sob. "You're awake."
"So are you." Katsuki's thumb traced the line of Izuku's jaw. "Come here."
Izuku rose on his elbow, careful of the wires, of the bandages, of the fragile new thing beating in Katsuki's chest, and pressed his lips to his grandfather's. The kiss was soft, tender, a slow and deliberate prayer of gratitude. Katsuki's hand slid into his hair, holding him close, and when they broke apart, his eyes were wet. "Thank you," he whispered, and Izuku knew he wasn't talking about the surgery. "For stayin'. For believin'. For lovin' a mean old bastard like me."
Izuku laughed, watery and bright, and rested his forehead against Katsuki's. "Forever, Papa. I'm not going anywhere."
They lay there for a long moment, the only sound the steady lub-dub of Katsuki's new heart beneath Izuku's ear. A sound that meant tomorrow. A sound that meant the baby would know their father. Izuku's hand, still splayed over Katsuki's chest, began to move—slow, reverent, tracing the edge of the bandage, then sliding lower over the firm plane of his stomach. Katsuki's breath hitched, a sharp intake that wasn't pain.
"Baby boy." His voice was still a rasp, dry from the tube, but there was a warning in it—or maybe an invitation. Izuku didn't stop. His fingers found the waistband of the hospital gown, slipping beneath it, brushing the coarse hair that trailed down from Katsuki's navel. The skin was warm, alive, his.
"I thought I lost you," Izuku whispered, his voice cracking on the words. His hand kept moving, tracing the v-line of muscle that had softened just slightly from the weeks in bed, but was still there—still him. "I sat in that chair by his bed for three days. I watched them wheel you away. I didn't know if you were coming back." His fingers found the head of Katsuki's cock, half-hard already, and wrapped around it with a gentleness that made Katsuki's jaw clench.
"Izuku." Katsuki's hand came down, covering Izuku's, not pushing it away—just holding it there, his calloused fingers lacing between Izuku's. "I'm here. I'm not goin' anywhere."
"I know." Izuku lifted his head, his green eyes meeting Katsuki's crimson ones. There were tears on his cheeks again, but he was smiling—a real smile, the kind that reached his eyes and made them crinkle at the corners. "I just need to feel you. All of you. To make sure." He squeezed gently, and Katsuki's cock twitched in his grip, thickening, lengthening, responding to the touch like it had a mind of its own.
Katsuki let out a shaky breath, his head falling back against the pillow. "You're gonna give my new heart a workout, brat." But there was no bite in it—just affection, just relief, just the raw, overwhelming gratitude of a man who had been given a second chance.
Izuku's fingers found the waistband of his shorts, and he lifted his hips with a careful slowness, peeling the fabric down his thighs, over his knees, until the cool hospital air hit his bare skin. He was already wet—had been wet since Katsuki's heart started beating on its own, since the surgeon smiled, since he'd climbed into this bed and felt the warmth of his grandfather's body against his. His cunt throbbed with a low, insistent ache, a pulse that matched the steady rhythm under his palm.
"Baby boy." Katsuki's voice was still rough from the waking up, but softer now, the rasp carrying something like wonder. His eyes tracked Izuku's movements, watched him kick the shorts free and shift his weight, straddling one of Katsuki's thighs. "The hell are you—"
"Shh." Izuku pressed a finger to Katsuki's lips, a gentle, trembling press. "Don't move. Just let me take care of you." He shifted forward, his thighs bracketing Katsuki's hips, his weight settling carefully over the broad planes of his grandfather's body. The hospital gown had ridden up around Katsuki's waist, exposing the thick curve of his cock, hard and heavy against his stomach. Izuku's breath caught—the sight of it, the proof of him, alive and real and here—and he let his hips roll forward, sliding the slick heat of his cunt along the length of it.
Katsuki's jaw clenched, a sharp hiss escaping through his teeth. His hands fisted in the sheets at his sides, tendons standing out against the backs of his wrists. "Izuku—"
"Don't move," Izuku repeated, and his voice cracked, but it held. "Please, Papa. Just—" He rolled his hips again, slower this time, dragging his wetness along the shaft from base to tip, feeling the thick ridge of Katsuki's cock press against his clit, the friction sending a shudder through his whole body. "I need to feel you. I need to know you're really here."
Katsuki's chest rose and fell in a deep, shaky breath, his crimson eyes locked on the place where their bodies met. The head of his cock was slick now, shiny with Izuku's arousal, and his own was starting to respond despite the exhaustion and the drugs and the fresh incision in his chest—because he was alive, and Izuku was here, and nothing else mattered. "You’re gonna kill me, baby boy," he whispered, but it came out like a prayer.
Izuku's laugh was watery, spilling over into a sob. He leaned forward, his forehead pressing against Katsuki's, their breath mingling as he rocked his hips in a slow, grinding rhythm. The slide was wet and hot, his pussy lips parting to grip the sides of Katsuki's cock, not taking him inside—just rubbing, just proving, just feeling him hard and thick and pulsing against the most vulnerable part of him. "I'm not going to kill you," Izuku breathed, his lips brushing Katsuki's. "I'm going to keep you alive forever."
Katsuki's hand came up, slow and deliberate, and settled on Izuku's hip. Not gripping, not guiding—just resting there, a warm weight that said I'm here. "Then keep goin'," he rasped, his thumb tracing a small circle on Izuku's skin. "Show me."
Izuku's hips moved in a steady, desperate rhythm, his cunt dragging along the full length of Katsuki's cock, leaving a trail of slickness across the older man's stomach. The sound was wet and quiet, a soft, rhythmic shush-shush-shush that filled the recovery room alongside the steady beep of the monitors. Izuku's eyes were closed, his face pressed into the curve of Katsuki's neck, his breath hot and uneven against the older man's skin. He could feel everything—the throb of Katsuki's cock against his clit, the warmth of the calloused hand on his hip, the steady rise and fall of the chest beneath him, and beneath that, the new heart, beating strong and sure. Lub-dub. Lub-dub. A sound that meant tomorrow. That meant their baby would know their father. That meant he hadn't lost him after all.
"I love you," Izuku gasped, the words muffled against Katsuki's throat, and he felt the older man's hand tighten on his hip, felt the answering throb of the cock beneath him, felt the tremor that ran through Katsuki's whole body. He rolled his hips harder, faster, chasing the friction, chasing the proof, chasing the feeling of being this close to the man who had given him everything. "I love you I love you I love you—"
Izuku shifted his weight, his thighs trembling as he lifted his hips just enough to align the head of Katsuki's cock with his entrance. The slick heat of his own arousal made the slide inevitable—gravity and want pulling him down, the thick crown pressing against his folds, stretching him open with a slowness that felt sacred. He sank onto it inch by inch, his breath catching, his eyes locked on Katsuki's face, watching the way his grandfather's jaw went slack, the way his crimson eyes fluttered closed, the way his chest rose and fell in a deep, shuddering breath. Full. He was fully inside him, buried to the hilt, and Izuku felt the pulse of him—the throb of blood and life and a second chance—deep in his core.
Tears spilled over before he could stop them, hot and silent, tracking down his cheeks and dripping onto Katsuki's bandaged chest. He didn't wipe them away. He let them fall, let them soak into the gauze, let them be proof that this was real—that Katsuki was alive, that his heart was beating, that the cock buried inside him was hard and hot and his. "I can feel you," Izuku whispered, his voice cracking on the words. "Inside me. I can feel your heart."
Katsuki's hands found his hips, resting there with a gentleness that belied the size of them, the strength Izuku knew they held. His thumbs traced small circles on the jut of Izuku's hipbones, and his voice came out rough, wrecked, beautiful. "I can feel you too, baby boy. Everywhere."
Izuku rolled his hips—slow, deliberate, a wave of motion that dragged Katsuki's cock against his inner walls, pulling a gasp from both of them. He did it again, and again, each roll a prayer, each inch of movement a declaration. He wasn't chasing pleasure. He was chasing proof. The slide of skin, the wet heat of their joining, the way Katsuki's breath hitched with every forward tilt—this was the evidence he needed, written in his own body.
He leaned forward, careful of the wires, the tubes, the fresh incision, and pressed his forehead to Katsuki's. Their breath mingled, warm and uneven, and Izuku let his hips still, let himself just be—full of his grandfather, pressed against his chest, feeling the steady lub-dub of the new heart beneath his ear. "I thought I lost you," he breathed, the words barely audible. "I sat in that chair for three days and I kept thinking—what if I never get to feel this again? What if I never get to feel you inside me? What if our baby never gets to know—" His voice broke, and he pressed his lips to Katsuki's throat, tasting salt and antiseptic and something that was just him.
Katsuki's hand came up, slow and heavy, and cradled the back of Izuku's head, fingers threading through the green curls. "I'm here," he rasped, his voice a dry echo of itself. "I'm not goin' anywhere. You hear me? I got a new heart. A second chance. And I'm gonna spend every second of it with you."
Izuku let out a sound that was half sob, half laugh, and pressed closer, his chest aching with the weight of it all. He rolled his hips again, a slow, grinding circle that made Katsuki's breath stutter, and felt the older man's hands tighten on his hips—not guiding, just holding, just feeling. "I know this is wrong," Izuku whispered, the words spilling out before he could stop them. "I know that. We're—you're my grandfather. This goes against everything. Science, society, morality—all of it. And I don't care." He lifted his head, meeting Katsuki's crimson eyes with his own tear-blurred green ones. "I don't care. Someone listened. Someone gave me this. Gave us this. And I'm not going to waste it feeling guilty."
Katsuki's thumb brushed the tears from Izuku's cheek, rough and tender. "That's my boy," he murmured, and there was pride in his voice, raw and unmistakeable. "You're my boy. And I don't give a damn what anyone thinks. You're mine, and I'm yours, and that's all that matters."
Izuku's hips moved again, slower now, a gentle rocking that didn't push either of them toward climax but kept them close, kept them connected. He could feel Katsuki's cock twitch inside him, responding to the motion, and the proof of it—the proof that this body was alive and here—made fresh tears spill down his cheeks. He didn't chase the orgasm. He didn't want it. He wanted this: the fullness, the warmth, the steady rhythm of three heartbeats—one old, one new, one growing in his belly—pulsing together in the quiet of the recovery room.
His body began to sag, the exhaustion of three sleepless nights finally catching up to him. He shifted, careful and slow, letting himself settle against Katsuki's right side, his cheek pressed to the warm skin above the bandages, his ear directly over the new heart. Lub-dub. Lub-dub. A sound that meant tomorrow. That meant their baby would know their father. That meant he hadn't lost him after all.
"Stay inside me," Izuku murmured, his voice already thick with sleep. "Please. Just—stay."
Katsuki's arm wrapped around him, pulling him closer, and his voice came out rough and gentle. "I'm not goin' anywhere, baby boy. I'm right here."
Izuku's hand found Katsuki's, their fingers lacing together, and he pressed their joined hands against his own chest, over his heart. The blanket was still pooled around Izuku's waist, and he reached down, grabbing the edge and pulling it up, over his bare back, over Katsuki's exposed chest, hiding their nudity from the door, from the window, from the world. Just the two of them, cocooned in thin hospital cotton, connected in the most intimate way two people could be.
He could feel the pulse of Katsuki's new heart through his palm, through his chest, through the cock buried deep inside him. A rhythm that matched the beat of his own heart, that matched the flutter of their baby moving in his belly. Everything was aligned. Everything was right.
"I love you, Papa," Izuku whispered, the words pressed into Katsuki's skin, absorbed by the steady rhythm beneath it.
Katsuki's hand tightened on his, and his voice came out a dry, cracked whisper. "I love you too, baby boy. More than I got words for."
Izuku's eyes fluttered closed, his body sinking into the warmth of the bed, the warmth of Katsuki's body, the fullness of being held and filled and home. The steady lub-dub of the new heart played under his ear like a lullaby, and for the first time in three days, he let himself believe that everything was going to be okay.
He didn't move. He didn't need to. He just lay there, cockwarming his grandfather's cock, feeling the throb of blood and life and a second chance pulse through him with every beat of the heart beneath his cheek. A heart that was Katsuki's now. A heart that would keep beating for years to come.
A heart that meant their story wasn't over yet.
The morning light crept through the blinds, painting stripes of gold across the hospital floor, and Izuku let himself drift on the edge of sleep, held safe in the arms of the man who had been given a miracle. The man who was his grandfather. The man who was his lover. The man who was the father of his child.
The man who was, against all odds, still alive.