The two people and the cat arrived at the outskirts of Fuyuki City.
Doraemon took out his [Magnifying Light] and shone it on the [Entry and Exit Mirror]. The mirror expanded rapidly, growing to a size visible even to the naked eye.
"Alright," Doraemon said.
He hopped into the mirror. The surface rippled like water, half of his body disappearing into the other side. Stretching out his furry paws, he called back to the others."You two, come on in. Hurry."
"The raccoon cat's tricks are really something," Miyamoto Musashi remarked with admiration. She approached the mirror and touched its surface, causing more ripples to spread. "It's unbelievable… but without a doubt, this is another world."
Musashi was no stranger to traveling between worlds. She knew the sensation well.
"Master, I'll go first~♪ I'll be back once I've checked that it's safe." She flashed a carefree smile.
Muramasa Shirou shook his head. "No need. There's no life in the mirror world."
One after another, the two stepped through the mirror. Doraemon followed, pulling out an [Invisibility Cloak] to conceal the entrance and erase any trace of it.
The moment Shirou entered, he felt gravity reverse. Pulling himself from the mirrored pool, he looked around—everything seemed the same, yet subtly… wrong.
As the name implied, the mirror world reversed reality: the sun's path across the sky was backwards, text was mirrored, even tree rings spiraled the opposite way.
Shirou examined the Command Seal on his hand. His connection to the Greater Holy Grail system in the real Fuyuki wasn't severed, but now there was also a faint link to this world's mirror Grail system.
"It really is an opposite world. Even the positions of the moon and stars are different," Musashi said, gazing upward. The evening breeze played with her long hair, making the bright flower on her kimono look oddly lonely.
Whenever she entered a new world, she thought of home—knowing she could never return.
"By the way, Musashi, here's something for you," Doraemon said, pulling a [Bamboo Copter] from his pocket and handing it over.
"What's this?"
"[Bamboo Copter]. Wear it on your head, and you can fly."
"No way. This tiny thing… can actually fly?"
Before she could finish her skepticism, she saw Shirou already wearing one. The blades spun, and he slowly floated upward.
She stared, struggling to imagine how such fragile blades could lift a person's weight.
The truth was, everyone—including Shirou—had misunderstood the [Bamboo Copter]. The spinning blades weren't like a helicopter at all. The real mechanism was an internal anti-gravity system.
So what were the blades for? Pure showmanship.
"Unbelievable. This raccoon cat is ridiculously capable. And me, the Master's Servant…"
Musashi's initial mix of amazement and disappointment vanished once she tried it herself. She zipped around in the air, laughing, striking various sword poses mid-flight.
"This is so much fun! Fly higher—higher! Let's go to the moon, and I'll see if my sword can cut it in half!"
It was hard to tell whether she was romantic, reckless, or simply berserk.
"Master, you're too slow!" she shouted. "This is boring—let's fill our stomachs first!"
Grabbing Shirou's hand, she pushed the [Bamboo Copter] to full power.
The moonlight caught in her hair and kimono as she soared ahead, her expression radiant—almost inhumanly beautiful. Shirou wondered how to describe it, that fleeting beauty that felt like it didn't belong to this world.
Soon, the lights of downtown Fuyuki glimmered below them. Landing, they found a supermarket and began "shopping" for free.
There were no people in the mirror world, and few fresh ingredients—only packaged food.
Even so, Musashi praised the food, especially cup noodles.
After eating, the group searched for a place to stay. Shirou chose the most luxurious Japanese-style mansion in Fuyuki—home to the real-world Matou family.
"Wait," Musashi said, stopping him before the heavy wooden doors. Her eyes glimmered with rainbow light. "Master, there's a barrier here."
"Barrier?" Doraemon asked nervously. "Sounds dangerous. Let's just go somewhere else."
"Don't worry," Shirou said calmly. "Musashi, can you break it?"
"Leave it to me. Piece of cake."
She drew a short sword from her waist, a strange light wrapping around the blade, and struck at the air itself.
Swish!
The invisible barrier rippled into view, turning pale blue like water trying to resist her slash.
Bang!
It shattered like a soap bubble.
The Matou family's magical barrier existed here too, but without anyone to maintain it, it was no match for a Servant of Musashi's strength.
"Well, Master? Pretty reliable, right?" she said with a smug grin, like a child fishing for praise.
"Reliable," Shirou replied.
"Hehe~." That was all it took to make her happy.
Inside, Shirou began to explore immediately. He hadn't chosen this place for comfort.
The [Two-Dimensional Heroic Spirit Summoning System] had assigned him a side quest: Save Matou Sakura. He had twenty-three days before she would be thrown into the insect pit by Matou Zouken.
The reward was 200 system points.
But even without a reward, Shirou couldn't ignore it. He might not share Emiya Kiritsugu's "hero of justice" ideals, but he still had a sense of right and wrong—and Zouken's actions were nothing short of monstrous.
Still, he couldn't act openly yet. Sakura was, for now, the legitimate adopted daughter of the Matou family, recognized by both the Tohsaka and Matou magus clans. If he tried to take her by force, he'd risk being misunderstood—possibly by Sakura herself.
For now, the priority was strengthening himself enough to win the Fourth Holy Grail War without relying entirely on Doraemon's gadgets.
After all, even in Doraemon's own world, the lesson was clear: you can't depend on tools alone. True crises demand your own strength.
Not that Doraemon lacked tools for developing strength.
Balancing gadgets with self-reliance wasn't hard in theory—though in practice, Doraemon's stories often overplayed the "don't rely on gadgets" theme, turning solvable problems into chaos.
And in any case, skill mattered too. Even someone like Nobita—generally hopeless—was a cosmic-level sharpshooter. In the Type-Moon world, that might even earn him the skill [God's Marksmanship].