The story begins with a boy leading an ordinary, unremarkable life. Kaito is a high school student, drifting through his days like a ghost in the hallways. Like any other boy his age, his heart beats for someone special—a girl in his class named Yuna.
Yuna is the class topper, brilliant and radiant, a star that feels light-years away from someone like Kaito. Despite his feelings, he could never find the courage to approach her. He remained a spectator in her life, watching from the shadows of his own hesitation. Beside him was his only close friend, Toru, who often tried to push him out of his shell.
One day, an announcement echoed through the classroom: an Adventure Survival Trip. The excitement was infectious, and almost everyone signed up, eager for the journey. But Kaito refused. Toru practically begged him, trying every trick to get him to join, but Kaito remained stubborn. He chose the comfort of his solitude over the thrill of the unknown.
The trip went on schedule, leaving Kaito behind in a quiet, empty city. That evening, to kill the boredom of his self-imposed isolation, he headed to the supermarket. On his way back, fate threw a curveball. He saw a child struggling, drowning in the water. Without a second thought, the "ordinary" boy vanished, and Kaito dived in, saving the child's life in a heartbeat.
The next day, the school was buzzing. The students had returned, filled with stories from the trip. Kaito sat at his desk, staring into space, his mind drifting toward Yuna as it always did.
But then, Toru approached him with a look that made Kaito's heart sink.
"Kaito... you should probably give up on Yuna," Toru said softly.
The words felt like a cold blade. Toru explained that while they were away, a boy named Jin had proposed to Yuna. And Yuna... she had accepted.
The world seemed to turn gray. Kaito sat in silence, the weight of his unspoken words crushing him. He had saved a life, yet he had lost his world. From that day on, he continued to come to class, but the Kaito who dreamed was gone. He was just a shell, moving through a life that now felt like a cruel joke played by time.
Even as the days passed, Kaito couldn't stop thinking, "What if I had just gone on that trip?" But he knew it was too late; the moment had slipped through his fingers, and nothing could be changed.
[Time Skip — The Final Days]
A few days remained before their high school life would officially end. Soon, they would all be heading off to college. By the end of school, even Toru had found a girlfriend. Only Kaito remained stuck, unable to pull himself out of the void that Yuna's absence had created. Yet, every time his eyes met Yuna's, the same old sadness washed over him all over again.
When the time for university came, the divide became even clearer. Yuna and Jin both went to Kohana University, the top-tier, elite institution in the country. Meanwhile, Toru and Kaito ended up at Seiryo University, which was nothing more than an average college.
[Time Skip — The Present Day]
Now, at present, everyone has passed out of college and started their professional lives. Kaito works at an MNC (Multinational Corporation). He is an incredibly hardworking employee, yet a deep, lingering sadness never leaves him.
He constantly looks back at his "Elite Time"—his school and college years—realizing he did nothing special with them. To make matters worse, he had a falling out with his best friend, Toru, during their college years, and they haven't spoken since.
Kaito desperately wants to go back and fix his past mistakes, but he knows that no matter how much he yearns for it, he is powerless. He is now completely alone, a man trapped in a life built on regrets.