It was a sticky Tuesday evening, the kind where the humidity made your shirt cling like bad code. Haruto Takemi, still riding the high of fixing Aiko’s home office, stood in her apartment, 2A, gripping a dog-eared baby book titled Toddler Taming: A Beginner’s Guide. His navy hoodie was flecked with lint, his glasses teetering on his nose, and his messy black hair looked like it had battled a windstorm and lost. Babysitting a three-year-old? Me? I barely survived the email fiasco. His pulse thrummed, half eager to impress Aiko, half braced for disaster. “Keep Emi safe for two hours,” he mumbled, nudging his glasses up. “No crashes, no bugs. And no daydreaming about that tech competition.”

Aiko burst out of her bedroom, tugging a blazer over her navy blouse, her long dark hair in a rushed braid. Her hazel eyes were lively but frazzled, a faint flush on her cheeks as she wrestled with a purse and heels. “Haruto, you’re a lifesaver,” she said, her voice warm but hurried. “Work sprung this dinner on me, and my sitter bailed. Emi’s a breeze—just feed her, change her diaper, keep her happy.” She gestured to a kitchen counter with a bottle, diapers, and a jar of mashed carrots, then to a living room less cluttered than before, though boxes marked “Emi’s Toys” and “Old Keepsakes” still loomed in the corner.

Three-year-old Emi sat on a bright play mat, hugging her stuffed rabbit, her big brown eyes studying Haruto like he was a new toy. “Hauto!” she chirped, waving a plastic dinosaur with a sticky hand.

“Uh, hey, Emi-chan,” Haruto said, crouching stiffly. Dinosaurs? I’m more of a binary guy. Aiko’s smile softened, watching them, then she snatched her keys. “You’re golden, Haruto. Emergency numbers on the fridge, back by nine.” She paused, glancing at her phone—a missed call from an unknown number flashed before she shoved it away. “Thanks, really.” She kissed Emi’s forehead, waved, and darted out, leaving Haruto in a quiet apartment that felt like a high-stakes debug session.

“Right, Emi-chan, game on,” Haruto said, attempting confidence. He started with the bottle, which Emi slurped eagerly, but the mashed carrots were a war zone. Half splattered his hoodie, the rest decorated her dinosaur. “You’re a messy coder,” he teased, wiping her cheek. Emi giggled, smudging carrot on his glasses. This is… survivable. Maybe.

The diaper change was next. Haruto spread the changing mat, book propped open. “Step one: old diaper off,” he read, fumbling the tabs. Emi wiggled, kicking his wrist, and the diaper sprang free, unleashing a stench that hit like a system crash. “Critical error!” he gasped, grabbing a new diaper. But Emi snatched the baby powder, squeezing it with a gleeful pffft. A white puff erupted, coating Haruto’s hair and glasses like a pixelated snowstorm. He coughed, blinking through the haze, then realized he’d taped the diaper on backward. Compile failed. Retry?

Emi’s lip trembled, her fussing rising. Haruto scooped her up, pacing frantically. “No tears, please!” His gaze hit his phone, and a lightbulb pinged. He pulled up an anime opening theme—cheerful, bouncy, with a soaring chorus. “Here we go, Emi-chan.” He rocked her gently, singing off-pitch, “*Kimi no hikari, shining bright!*” Emi’s fussing faded, her eyes wide, then she squealed, clapping her tiny hands. Haruto’s chest swelled. Nerd skills: one, chaos: zero.

When Aiko returned at 8:50, the apartment was a battlefield: powder dusted the floor, carrot stains marked the table, and Haruto’s hoodie was a Jackson Pollock tribute. But Emi slept in his arms, hugging her rabbit, the anime tune looping faintly. Haruto slouched on the couch, glasses fogged, hair a powdered mess, looking battered but triumphant.

Aiko paused in the doorway, her blazer rumpled, a tired but amused grin blooming. “Haruto, what happened?” she whispered, barely containing a laugh as she scanned the wreckage.

He jolted, careful not to wake Emi. “Uh, adventures,” he stammered, cheeks flaming. “Diaper glitch, powder storm, but the anime song saved us. She’s fine, promise!” Don’t let her think I’m a total failure.

Aiko knelt beside him, her hand grazing his arm as she checked Emi. “You’re amazing, Haruto,” she said softly, her hazel eyes glowing. “Most guys would’ve panicked. You stuck it out, and she’s content. That’s huge.” Her gaze flicked to the “Old Keepsakes” box, its label blurred by Emi’s crayon scribbles, and her smile wavered briefly. “I owe you big—maybe dinner?”

Haruto’s heart stuttered. Dinner? With Aiko-san? “No big deal,” he mumbled, standing to pass Emi over, nearly tripping on the dinosaur. Aiko steadied his elbow, their faces close for a split second. Her lavender scent scrambled his brain, and he lurched back, blurting, “Gotta study for that tech competition. Big deadline.”

Aiko laughed, tucking Emi into her crib. “Rest up, tech hero. And thanks—for everything.” Haruto shuffled back to 2B, his mind a swirl of powder clouds, anime melodies, and Aiko’s grin. Babysitting: cleared. Heart: fatal exception. In 2A, Aiko glanced at her phone, a new text from the unknown number unanswered, her expression clouded as she dimmed the light.