"What's going on? What exactly happened?" I asked, looking at Doraemon, who had just been through an intense battle.
"Another strange army invaded the Mu Federation. That army is probably the one from Oniiwa Castle that El mentioned!" Doraemon said, his face looking grim, but he continued.
"Their submarines are much larger than the Mu Federation's. Our weapons could barely penetrate them. Without breaking their armor, the fight was really tough!"
"Most importantly, the people coming out of their submarines were all robots—hard to damage!"
"Even you couldn't handle it, Doraemon?" I said in shock.
"Not exactly. Later, we relied on gadgets and managed to repel the Oniiwa Castle army!"
Shizuka stepped in to explain for Doraemon.
"But there were just too many of their soldiers. We couldn't handle them all at once, and the Rebounding Cloak that Seiko was holding didn't have any offensive power anyway."
"Then, in a moment of carelessness, she was captured by the Oniiwa Castle army!"
Shizuka grew worried as she spoke.
"Seiko won't be in danger, right?"
"It's all my fault. I didn't repel them in time, which gave the Oniiwa Castle army the opening to capture her!" Doraemon's face was full of self-blame.
"Doraemon, it's not your fault. No one knew the Oniiwa Castle army would suddenly attack!" I comforted him, hoping he'd feel better.
"Since Seiko was captured, that means she must have some value to Oniiwa Castle. She should be safe for the short term."
Everyone nodded in agreement with my reasoning.
"Then let's go to Oniiwa Castle and rescue Seiko!" Doraemon perked up.
"Okay, but there's one thing I need to do before we go!"
I agreed with Doraemon's suggestion, but I had to handle something first.
I didn't explain—instead, I used instant teleportation to leave, leaving the others puzzled.
When I returned, I had someone with me.
"El?"
Everyone was confused why I'd brought this underwater person along.
We'd just been fighting to the death moments ago.
"The Mu Federation has been fighting Oniiwa Castle for so long—they should know them best!" I explained.
El had been reluctant at first when I asked for his help, since we'd just been enemies.
But when he heard we were going to Oniiwa Castle, he agreed immediately.
For this trip to the Atlantic, we weren't using the underwater bicycles but a Mu Federation submarine. The bikes' protection and capacity were just too limited.
On the submarine, El explained why he was helping us, and along the way, he introduced the origins of Oniiwa Castle.
"The story starts from thousands of years ago."
"While you land-dwellers were still in the Stone Age, we underwater people had already built a highly advanced civilization in the ocean depths!"
El said this with pride, and I got the feeling he was doing it on purpose—to salvage his nation's dignity.
El continued his explanation.
"There were hundreds of nations underwater, eventually divided into two major federations: the Pacific's Mu Federation and the Atlantic's Atlantis."
"I know that—it's the nation that sank into the sea and was destroyed, right?" Suneo said in surprise, recognizing Atlantis.
"That's just a legend. Atlantis was originally an underwater nation," El corrected Suneo.
"So they were underwater people too! Then why were they destroyed?" Suneo asked curiously.
El waved his hand, signaling to let him continue.
He went on, "Later, as the two federations developed to a certain point, they began military competition over resources, accelerating the development of new weapons!"
"Finally, Atlantis created the Ghost Horn Bombs—similar to what land-dwellers call nuclear missiles."
"Then, they notified the Mu Federation that if we didn't surrender, they'd flatten the Pacific—and it wasn't just a threat."
At this point, El swallowed hard, as if imagining the scene, but he continued.
"Because countless Ghost Horn Bombs were ready, and with the press of a button, they could fly to every corner of the world—they had them all set up."
"But that's strange. Wouldn't that harm the Atlantic itself too?" Doraemon asked skeptically.
"They had preventive measures. They set up a massive protective shield around Atlantis—invisible and intangible, extending from the seafloor to the sky. It could completely isolate radiation," El's words instantly cleared up Doraemon's doubt.
"But in the end, that became their downfall, leading to Atlantis's destruction." El sighed at this point.
"Why?" Everyone's curiosity was piqued.
"Because of a failed nuclear test, the radiation spread throughout the federation. But due to the protective shield, the outside world wasn't affected—the entire damage was contained within the small shield, instantly killing everyone."
"Of course, that's not why I'm here to help you." El then explained his main reason for coming.
"Although Atlantis was destroyed, the Ghost Horn Bombs and Poseidon remained."
"Poseidon?" Everyone was confused—wasn't that the name of the sea god?
"Poseidon is a computer built for this purpose—an automatic system that retaliates immediately upon detecting an enemy attack."
"Because the underwater volcanoes near Bermuda might erupt, Poseidon could mistake it for an enemy attack and retaliate. Then, the Ghost Horn Bombs would launch worldwide, leaving not even a blade of grass or a tree—turning the world into a dead one."
"So, I believe with your strange technology and great strength, you can solve the Oniiwa Castle problem. That's why I'm here to help!"
Before everyone could respond to El's plea...
The group was momentarily stunned by El's description! Doraemon was dumbfounded—how had rescuing one person turned into saving the world?
But they now understood the general situation: the Bermuda Triangle in the Atlantic was where Oniiwa Castle, the former hub of the Atlantis Federation, was located—just like the Mariana Trench for the Mu Federation.
"Anyway, we have to give it our all!" Faced with this world-ending crisis, Doraemon felt he couldn't ignore it.
Everyone nodded solemnly. This time, it wasn't just about rescuing Saotome Seiko—they also had to destroy Poseidon. Their mission was heavy!
However, as everyone chatted and discussed on the submarine, it slowly approached the vicinity of Oniiwa Castle.
But the scene outside left everyone in shock!