—We're going to look for Professor Deppler's hideout with the radar cane.
Nobita held his cane with both hands and struck the ground solemnly. Then he let it go.
—Tell us where Professor Deppler is!
The cane vibrated… and began to tilt on its own. It fell to one side, but not completely. The handle remained suspended in the air, pointing in a direction without touching the ground.
—Huh? It didn't fall all the way?
—Ha, ha… maybe it's broken too? —Kurt murmured.
—Wait a moment —Noah said quietly.
He approached a nearby column. On it was a simple painting: a depiction of some stairs. Nothing special at first glance.
Noah placed his palm on the canvas, and the painting vibrated.
The image rippled as if it were water. The stairs began to extend outward, solidifying in the air until they became a real structure that ascended into the darkness. A secret passage was revealed.
—Hey, Noah, you got it right! —Gian exclaimed.
—See, Nobita? Even a little kid has more Holmes instincts than you! —Suneo added with a laugh.
Nobita frowned but didn't respond.
Just as they were about to go up, a viscous sound floated behind them.
A small pink slime advanced, bobbing in the air.
—Huh? Poppo? You can't come here. I've told you that —Kurt said with a worried tone.
Poppo floated until he was right in front of him. He stared at him for a few seconds, as if something didn't fit. Then he slowly turned and drifted over to Shizuka, landing on her head.
—Poppo, are you comfortable up there? —she asked, amused.
—Ha, ha… there's no understanding him. Maybe he likes girls more —Kurt laughed, though the laugh sounded dry.
Noah narrowed his eyes and smiled.
Without warning, thick vines sprouted from the ground and coiled around Kurt, trapping him firmly. Only his face remained free.
—Huh? What are you doing, Noah?! Let Kurt go! —Nobita shouted.
—Calm down —Noah replied calmly—. This isn't Kurt, to begin with.
—Huh? What do you mean, it's not Kurt?
—Yeah, what do you mean it's not me? Can't you see it's me?
—You'll see.
Noah approached and pressed the nose of the supposed Kurt.
There was a click, and Kurt's body began to deform. His skin lost color, his features simplified, and in a matter of seconds, a wooden doll appeared before the group.
—A Copy Robot! —Doraemon exclaimed.
—That's right. This wasn't Kurt to begin with —Noah said, releasing the vines.
The doll fell inert to the floor.
—Then… where is the real Kurt? —Shizuka whispered.
Noah looked towards the newly revealed staircase.
—Isn't it obvious? We were just facing him a little while ago.
—You mean… —Nobita murmured.
—Kurt is DX!
—Well, are we going in or not?
Without waiting for an answer, Noah was the first to ascend the stairs.
The others, still processing the revelation, followed him one by one into the darkness.
—Professor! Nobita and the others are here!
The real Kurt burst into the underground room, out of breath.
—I know —Professor Deppler replied without taking his eyes off his work—. But I'm at a very delicate moment.
Deppler held five tiny microchips between his fingers. He inserted them one by one into slots distributed around the machine's core.
Those microchips were the heart of everything.
Years ago, before his arrest, he had hidden them inside six gadgets sent to the repair factory. Among them, Doraemon's bell.
—Only one remains —he murmured—. Come on, Ginger. Give me that object.
Ginger, leaning against a side console, made a face.
—Ugh… and I liked it so much.
She bent down, untied the yellow bell attached to her shoe, and tossed it to her grandfather reluctantly.
At that very moment, the group burst in through the secret staircase.
They arrived just as Deppler, without hesitating, split the bell in two with a thin-bladed knife.
—Aaaay…
Doraemon stood rigid, staring at the two open halves in the professor's hand.
Deppler extracted a tiny microchip from inside and held it up to the light, satisfied.
—Hehehe… I have them all now!
He inserted the final piece into the machine's core.
—Children —he said, turning to face them—. You will witness my feat. You will attend an event that will change the world!
The machine reacted instantly.
A white radiance expanded from the center, forcing everyone to cover their eyes.
—Hehehehe… it has finally begun.
At that same second, something activated in Noah.
His Elder Blood responded without warning.
The noise of the world faded away.
The light from the machine distorted before his eyes, and suddenly, he was no longer seeing the present.
He saw what would happen next.
The professor activating the device with a triumphant smile.
The machine extending an invisible wave throughout the entire floating museum.
Deppler's plan was to replace the Fullmetal alloy in all gadgets with his new Deppler metal. To rewrite the very foundation of their technology.
But it wouldn't work as he intended.
In the vision, the wave would disintegrate all gadgets created with Fullmetal alloy.
The gadgets began to dissolve into brilliant particles. Display cases, support systems, structural mechanisms… everything built with that alloy collapsed from within.
The floating museum would begin to crumble.
But the worst would happen shortly after.
The small artificial sun in the basement —contained by a device made from the same alloy— would be freed as its confinement disintegrated and would begin to grow uncontrollably.
The vision cut off, and Noah returned to the present with a blink.
Professor Deppler raised his hand towards the activation panel.
—I will change all the Fullmetal alloy in this museum into Deppler metal of my own creation! Ha, ha, ha!
Noah didn't wait for him to finish the sentence.
—Mokuton!
The ground erupted.
Thick roots burst from the floor. One part coiled around the professor's body, immobilizing him before he could touch the controls. The rest enveloped the machine, creaking against the metal as they tore it from its anchors.
—Noah! —Nobita shouted.
But Noah was already moving.
In a quick motion, he snatched the complete Sherlock Holmes set from Nobita and jumped next to the machine wrapped in his roots. Before everyone, he pulled out Doraemon's 4D pocket and placed it on his own chest.
—That's my pocket! So it was you who stole it! —Doraemon exclaimed.
Noah shrugged.
A robot turtle poked its head out from inside, trying to bite his fingers, but a root grabbed it and flung it against the wall.
Calmly, Noah stored the Denkomaru katana and the Sherlock Holmes set inside the pocket.
With one hand, he manipulated a vine that held the edge of the 4D pocket and stretched it open like an elastic mouth. The other roots lifted Deppler's enormous machine and pushed it inside. The device disappeared into the infinite space of the pocket.
It all happened in a matter of seconds.
No one had time to react.
Noah looked at them one last time.
—Goodbye.
He opened a portal beneath his feet and let himself fall.
He returned to Nobita's room in the 21st century. The evening light came through the window as if nothing had happened.
—Good thing I had marked this place… —he murmured, relieved.
He knelt in front of Nobita's desk and pulled out the drawer where the time machine was connected. After examining it for a few minutes, he learned how to deactivate it. He carefully disconnected it and also put it inside the 4D pocket.
Noah stood up and, without looking back, opened one final portal and left that world without granting anyone the chance to stop him, returning home.