The world was filled with color the day they met.
It was the beginning of spring, and the sakura trees around the small neighborhood park were already blooming, scattering soft pink petals into the clear blue sky. Three-year-old Yuto Kisaragi, with messy blue hair and curious dark blue eyes, clutched his father's hand tightly. He didn't like meeting new people — new people were scary.
"Come on, Yuto," his father chuckled. "I told you, my friend's daughter is very nice. You'll like her."
Yuto only tightened his grip and shook his head shyly.
On the other side of the park, Noa Kanzaki stood next to her own father, her tiny pink twin-tails bobbing as she shifted nervously. Her big emerald eyes flickered around the park, landing briefly on Yuto before quickly looking away, cheeks burning. She clutched the hem of her pastel dress as if it were a shield.
When the two fathers greeted each other with laughter and backslaps, Yuto and Noa remained frozen a few feet apart, stealing awkward glances at each other.
"She's your age, Yuto! Why don't you say hello?" his father encouraged.
Yuto fidgeted, then managed a soft, almost inaudible, "...Hello."
Noa peeked up at him through her eyelashes, then whispered back, "H-Hello..." Her voice was so small it almost got lost in the breeze.
The fathers laughed again and left them to play, walking toward a bench to talk.
For a long moment, Yuto and Noa just stood there, staring at their shoes. Then Yuto noticed a sakura petal had landed in Noa's hair. Before he could think, he pointed at her head. "...Petal."
Noa blinked in surprise, touched her head, and giggled softly when she found the pink petal. She looked at Yuto again — this time really looked — and saw that he wasn't so scary after all. He was just as nervous as she was.
Without a word, she picked up another petal and held it out to him.
Yuto hesitated, then took it, his tiny fingers brushing against hers.
That small, shy exchange was the beginning.
They became inseparable after that.
At kindergarten, they were always paired together. Noa loved to draw, and Yuto loved to build things out of blocks. Sometimes he would bring her little block "houses" and she would decorate them with drawings.
When the other kids teased Noa for being too quiet, Yuto stood up for her, his small fists clenched, his shy bravery surprising even the teachers. And when Yuto tripped and scraped his knee, it was Noa who wiped away his tears with her tiny handkerchief, her own eyes filled with worry.
"Don't cry, Yuto," she said seriously. "I'm your friend."
Those words stayed with him longer than the pain in his knee.
By the time they were six years old, they walked to elementary school together every day, their tiny hands swinging between them.
Their fathers had remained close friends, and their houses were only a few streets apart. Often, Yuto would sneak out after dinner just to sit under the old sakura tree in Noa's backyard. Noa would join him with a blanket and two cups of warm milk.
Under the stars, they talked about everything — about how they wanted to become heroes, how they would always protect each other, and how they would never, ever be apart.
One evening, Yuto pulled a small, shiny pebble out of his pocket and pressed it into Noa's hand. "It's...a promise stone," he said, face burning red. "We have to stay together forever."
Noa clutched the stone tightly to her chest and smiled the brightest smile Yuto had ever seen.
"Promise," she whispered.
As the years passed, middle school brought change.
Yuto shot up taller, his blue hair growing messier, his quiet bravery becoming more obvious. Noa's pink hair grew longer, and she often tied it back with a ribbon Yuto had given her one birthday.
Other people started noticing Noa — boys would stare, girls would whisper. Yuto didn't like it, but he didn't know why. He only knew that when Noa smiled at someone else, a strange ache grew in his chest.
Noa, too, noticed that Yuto was becoming... different. His voice was deeper, his eyes more serious. When he smiled now, it made her heart skip strangely.
They still walked to school together. They still shared their favorite bench under the sakura trees. But words became harder to say. Silences stretched longer between them.
Sometimes, when Noa looked at Yuto, she remembered that little boy who had once shyly offered her a sakura petal — and she wondered if she had already fallen in love back then, without realizing it.
On the first day of high school, they stood under the same sakura tree where they had made their childhood promises.
Yuto, now sixteen, was tall and handsome, his dark blue eyes steady but nervous. Noa, fifteen, had grown into a beautiful young girl, her soft pink hair fluttering in the spring breeze, her emerald eyes shining.
Neither spoke for a long time.
Finally, Yuto took a shaky breath. "Noa..."
She looked up at him, clutching the small necklace she wore — the one that held the promise stone he had given her years ago.
"I want to protect you," he said, voice low. "Not just like when we were kids. I... I want to be with you. Always."
Noa's heart pounded so loudly she was sure he could hear it.
"I know," she whispered, stepping closer. "I've always known."
And when Yuto leaned down to kiss her forehead, their first touch as more than childhood friends, it felt like the world — their world — had been waiting for this moment all along.
The sakura petals swirled around them, carrying their childhood promises into a future they would now face together — side by side, heart to heart.