A splitting headache.
That was the first thing Nohara Yoichi felt when he regained consciousness.
Just a moment ago, he had been in the office, rushing to finish a proposal in front of his computer. After working overtime for three days and nights straight, his vision had suddenly gone black—and he collapsed.
"…Am I in a hospital?"
Yoichi forced his eyes open.
But instead of the familiar white ceiling and IV drips, what greeted him was… a Japanese-style room filled with the warmth of everyday life.
Tatami mats. A tokonoma alcove. A hanging scroll with elegant calligraphy.
No matter how he looked at it, this was a traditional Japanese home.
"…Something's wrong. Seriously wrong."
Yoichi struggled to sit up and looked around.
The room wasn't large. The furnishings were simple—almost old-fashioned. A bulky desktop computer sat on a desk, with several manga and magazines piled beside it, all in Japanese.
He looked down at his hands.
They were younger. Slender.
Not his.
His real hands had pronounced knuckles and faint calluses from years of typing.
"…What's going on? A movie set? A prank?"
His heartbeat quickened.
Then an absurd yet unavoidable thought surfaced—
"…Don't tell me… I've been isekai'd?"
At that moment, a flood of unfamiliar memories surged into his mind like a crashing tide.
These memories belonged to a 20-year-old Japanese man named Nohara Yoichi—a distant relative of Nohara Hiroshi from his mother's side.
His parents had passed away early, and he had grown up in the countryside with his grandmother. After recently graduating high school, he heard that his cousin Hiroshi was doing well in Kasukabe, near Tokyo. Hoping to find a job, he came to the city to rely on him.
He had arrived just yesterday and was temporarily staying in the guest room of the Nohara household.
Exhausted from the journey and slightly sick, he had slept until now.
"…Nohara Yoichi… Nohara Hiroshi… Kasukabe…"
Each word hit him like a hammer.
Nohara Hiroshi…
Wasn't that the salaryman from Crayon Shin-chan? The unlucky dad who loved beer and had notoriously smelly feet?
And Kasukabe…
That was Shin-chan's hometown!
"…I… I've transmigrated into Crayon Shin-chan? And I'm Hiroshi's cousin?!"
Yoichi felt like his brain was about to shut down.
He had grown up watching Crayon Shin-chan. He knew it inside and out.
That five-year-old kid—wearing a red shirt and yellow shorts, constantly doing inappropriate dances, blurting out outrageous comments, and causing chaos wherever he went…
Just thinking about seeing that "little devil" every day made his scalp tingle.
"…Calm down. Stay calm."
He took a deep breath, forcing himself to think clearly.
Transmigration was already a fact. There was no point denying it.
First, accept it.
Then survive.
At the very least, as a relative of the Nohara family, he didn't need to worry about a place to stay—for now.
Next step: find a job.
And then… adapt to this new life.
Preferably while staying as far away as possible from that "troublemaker," Shin-chan.
Just as Yoichi was organizing his thoughts, a gentle knock came from the door.
Then a soft, slightly tired female voice followed:
"Yoichi-kun, are you awake? How are you feeling?"
It was Misae.
Yoichi's heart jumped into his throat.
One of the main characters!
He quickly composed himself and replied, trying to match the tone from his memories:
"Yes, sis… I'm awake. I feel much better now. Thank you."
The door slid open.
Nohara Misae, wearing an apron and her signature curly hair, walked in holding a bowl of steaming porridge.
"That's good to hear. Come on, eat this while it's hot—I made it just for you."
She set the bowl down with a warm smile.
Compared to her usual image—yelling at Shin-chan or going on shopping sprees—she seemed unusually gentle right now.
Seeing her in real life, up close, Yoichi couldn't help but feel dazed.
"Thank you… and sorry for the trouble," he said quickly.
"Oh, don't be so formal. We're family," Misae waved it off.
After asking a few more questions about his condition, she added:
"Hiroshi's at work, and Shin-chan is at kindergarten. I'll properly introduce you when they get back tonight. For now, just get some rest. Let me know if you need anything."
"Okay… thank you."
Misae gave a few more reminders before leaving the room.
Yoichi looked at the porridge, but his appetite wasn't great.
Sitting on the tatami, he tried to process everything that had just happened.
Then—
"I'm back—!"
A loud, energetic voice echoed from downstairs.
Yoichi froze.
That voice…
It was him.
That kid.
That five-year-old menace.
Nohara Shinnosuke was home.