The Thousand Sunny sailed on the calm sea for some time, and the gloom brought by the Expo was gradually dispelled by the sea breeze. The Straw Hat Pirates also returned to their usual noisy atmosphere, but in everyone's eyes, there was a sense of maturity and sharpness after experiencing life and death.
One of Nami's most important daily tasks was to observe and Log Pose. One morning, she suddenly let out a soft "Eh."
"Everyone, come quick! The pointer... something's wrong!"
The crowd gathered around, only to see that the pointer, which should have been steadily pointing to the next island, was now drawing circles slightly at a slow but continuous frequency, as if it were being interfered with or pulled by some invisible force.
"Huh? Is the pointer broken?" Luffy craned his neck, curiously trying to poke it with his finger, but Nami slapped him away.
"It's not broken," Robin observed carefully, "It's more like the pointer itself is unable to make a decision among several similar 'sources of attraction,' causing it to waver."
Franky checked the instruments. "Super~ Strange! The magnetic field in the surrounding sea is normal; it's not external interference."
Jinbe sensed the ocean current. "The current is calm; it doesn't seem like we're approaching a special sea area."
Allen's senses quietly spread outwards. In his "vision," there were indeed several "points" with extremely similar energy fluctuations in the vast depths of the sea ahead. They were like lighthouses in the deep sea, emitting a faint but common resonance, jointly interfering with the judgment of the Log Pose.
"It's not multiple islands," Allen said slowly, revealing the truth he had perceived, "But a massive... underwater structure with multiple energy overflow points. The pointers cannot determine which is the 'main entrance' or the 'core point'."
"An underwater structure?" Usopp immediately tensed up. "Is it... Ancient Weapon? Or another artificial island like Delta Island?"
Chopper clung to Usopp's leg in fear. "The seabed? It's so deep and dark!"
Luffy, however, was even more excited. "An underwater adventure! That's great! Maybe there'll be a giant octopus or treasure!"
Nami pulled out the nautical chart, carefully searched and compared it, and finally stopped in a blurry area marked "unknown risk".
"Based on the center area where the pointer is hovering and Allen's perception... we may be approaching a sea area known as the ' Echo Abyss.' Legend has it that it is unfathomably deep, and eerie ' Echo ' from the seabed, like a mixture of thousands of sounds, can often be heard, hence the name. Almost no ships dare to venture deep into it, and there are very few records about it."
" Echo?" Brook tilted his head (though he was just bones). "Yo ho ho ho~ Is it a soul like mine singing? Or some kind of ancient recording?"
Sanji imagined an underwater restaurant and mermaids. "If we could find a safe entrance, the food from the sea would definitely be incredibly delicious..."
Zoro, holding his sword, said, "As long as I don't get lost in some weird place again." (A flag has been raised!)
Ace's flame flickered. "I've never seen the excitement of the ocean depths before."
Allen's perception penetrated deeper into that sea area. He could not only "hear" the " Echo " that were mixed together from countless fragments of sound and indistinguishable to ordinary people, but he could also vaguely capture the weight of history, the embers of civilization, and a faint distress signal that seemed to come from the distant past.
"That abyss likely harbors a lost civilization, or... carries a forgotten history," Allen concluded. "Those ' Echo ' might be the resonance of residual information."
This conclusion instantly piqued Robin's interest. The lost civilizations might be closely related to the Poneglyph and the Void Century.
"It's decided!" Luffy waved his hand, pointing his rubber arm in the direction the pointer was hovering. "We'll go there! The lost civilization of the deep sea! Sounds incredibly interesting! Let's go!"
"Wait! Luffy! We need to prepare our diving equipment! And the situation down below is unknown!" Nami tried to stop him, but to no avail.
Franky immediately began excitedly checking the Thousand Sunny's diving system: "Finally, it's my turn to shine in diving mode! Super~!"
As Fish-Man, Jinbe is the best guide and protector when diving into the deep sea.
The Thousand Sunny adjusted its course and resolutely sailed towards the Echo Abyss full of unknowns and mysteries. A new adventure would begin in the depths of the ocean, ten thousand meters below the horizon where sunlight cannot reach.