The Thousand Sunny's prow cut through the glassy sea as dawn broke over the Red Line. Far above, the towering escarpment vanished into low-hanging clouds, its summit hidden from mortal eyes. On deck, the Straw Hats pressed forward, hearts pounding with excitement—and urgency. Luffy's voice rang out, bright and unshakable: "We've finally made it!" He pumped a fist, eyes gleaming with triumph and the weight of his brother Ace's fate looming in his mind. Zoro, leaning against the railing, cracked a grin, "We've been through hell to get here, huh?" Luffy nodded, voice soft with determination. "I will become the King of the Pirates!" Lucas, standing in the shadow of the mainmast, murmured to himself: "After this… maybe I'll take Lilian and travel the multiverse." His smile was faint but genuine. Nami's gaze sharpened as she surveyed the Red Line's sheer walls. "From here on, we're in Marine HQ territory, with Mariejoa next door. We have to stay alert." She caught both Luffy's and Lucas's eyes, a silent warning passing between them.
Within minutes, the crew adjusted its focus. With the Log Pose's needle locked down, Fish-Man Island lay somewhere beneath the swelling tides. Nami refused Lucas's suggestions—wanting to avoid the stunt he pulled to get to Skypiea. Instead, they opted for Franky's custom "Shark Submarine," tucked into a hidden well deck. A round of rock-paper-scissors decided the scouts: Robin, Luffy, and Brook would descend in the sub, while Zoro borrowed Lucas's clones to spar and refine his Four-Sword Style in the ocean breeze. Usopp and Chopper, brimming with curious excitement, slipped into the water alongside the Sunny—courtesy of a deployable swim platform Franky had installed. "All right—here we go!" Luffy declared into the transponder snail. The sub's hatch sealed, lights blinked inside, and with a mechanical hum, the Shark dove beneath the waves.
On deck, Nami leaned over the rail, voice crackling through her own snail. "How's it going down there?" she called. Silence, then Robin's measured tone: "No good. It's pitch black." Seconds later, Luffy's cheer cut through the depths: "Hey, did you guys see something shiny just now?" Brook's panicked squeal followed. "Uwahhhh! It's a sea monster! I'm gonna die!!—Oh, wait, I'm already dead! Yohohohoho!" His hollow laugh ended as he then in a serious tone asked Nami what underwear she's wearing. Nami's eyes narrowed. "Shut up and take this seriously, would ya?!" Usopp wiped his brow. "Man, that guy's got guts." Franky's voice boomed from the helm. "Remember—the Shark only goes down to five thousand meters. Keep an eye on the gauge!" A metallic creak echoed through the snail line. Brook gulped: "We've gone past five thousand meters!" Luffy let out a trembling laugh. "That's deep!" Lucas leaned beside Franky, tone dry. "I'm impressed their still alive at this point." The sub's lights flickered, water pressure groaning against the hull. "We're gonna get crushed!" Brook whimpered. "And it's that monster again…" Luffy's laugh faded into a tense whisper.
Back on the Sunny, Chopper rubbed his arms. "I don't think I want to ride that submarine." Usopp ducked his head. "Yeah… me neither." Sanji appeared with a flourish, trailing hearts in his wake. "Nami-swan! Your Thriller Bark Tart is served!" He laid down a golden pastry, steam rising in sweet swirls. He passed platters to Lucas, Franky, Chopper, and Usopp, each plate gleaming under the rising sun. "It's just like Skypiea again!" he declared. Nami sighed, tucking a strand of hair behind her ear. "We know where we're heading, but not how to get there." She turned to Lucas, voice insistent. "Come on—open your portal thingies and get us there already!" Lucas balanced his tart on one finger, frowning as he stirred the flaky crust. "It doesn't work like that. I have to see the destination or have been there atleast once." At that moment, the Shark Submarine breached the surface, hissing as water cascaded off its hull. Chopper pointed, voice triumphant. "They're back!" Nami straightened. "Welcome aboard." Luffy clambered up the hatch, stretching arms wide. "No luck—couldn't see the bottom, but it was fun!" Brook emerged, top hat crooked, cape dripping. "Yohohoho! My first time in a submarine!"
Nami checked her Log Pose. "Still pointing down… I wish I could've asked Lola and the others more about this." She tapped her foot as the sub bobbed gently at the Sunny's side. Suddenly, the sea ahead erupted. A giant sea monster breached, water crashing like a thunderclap. Brook shrieked. "It's that monster!" Luffy's eyes shimmered with challenge. "It followed us!" The creature's maw gaped, bristles of algae dripping as it roared into the sky. Luffy grinned, rubbery form stretching. "Don't think you can beat me on the surface!" With a mighty inhale, he unleashed a Gum-Gum Rifle, his fist rocketing forward at blinding speed. The fist collided with the beast's bulbous belly—THOOM!—sound waves rippling across the water. The monster's body convulsed, its massive gut buckling under the strike, and it expelled something from its mouth in a spray of saltwater.
Sanji watched the object arc through the air. "Huh… it spat something out." Two figures tumbled in slow motion, crashing onto the deck with a CRACK! On top of Sanji. Luffy's head snapped up. "A fish?" Nami took a step forward. "A person?" The smaller figure groaned but scrambled free. Sanji layed back, nose bleeding. The female form rose, hair dripping, eyes wide. "Wahhh! I—I flattened a human!" she wailed dramatically. Sanji knelt beside her. "I'm so sorry—are you okay?" She sniffed, voice trembling, then brushed wet hair from her face. "It's okay… don't worry about me." Behind her, the Straw Hats whispered in unison: "A mermaid?!" The newcomer's voice cracked with disbelief as she took in the crew. "Waaaah! So many humans here—so many eyes!"
Across the deck, the monster's great head lingered in the swells, but a single look at Luffy was enough to send it thudding back beneath the waves. "Yohoho—honored to meet you, lady of the sea."