The darkness outside was nearly complete now, a black so dense it seemed to absorb even the sub's own lights. The ocean floor stretched endlessly below, unseen but pressing upward with an invisible, relentless weight. Karl's hands hovered over the nanite controls, fingertips brushing the lattice interface, every muscle taut.
Agnes's holographic form hovered beside him, a soft glow cutting through the sub's dim interior. Her eyes were alert, pupils dilated as she scanned external pressure readings and the remaining demon activity. "This is it," she said softly. "Depths where even the strongest of them won't hold together. If we maintain stability, they'll start… snapping."
Karl's jaw tightened. "You mean, the pressure itself will do the work for us?"
"Exactly," she replied. "But we're walking a fine line. Push too deep, and the sub won't handle it. Nanite reinforcement only goes so far. But… it's the perfect ambush."
He nodded, feeling the thrill of control and danger both. "Alright. Let's make it happen."
He surged the nanites through the hull, reinforcing each plate, each seam, each bulkhead. The lattice shimmered under his fingers, absorbing and redistributing stress like a living skeleton. "I'm pushing it to maximum tolerance," he muttered. "We're not cracking, but barely."
"Good," Agnes said, voice calm but with that underlying excitement she always had when things were about to get dangerous. "Now… external pressure, on my mark. Hold steady."
Outside, the water thickened, becoming almost viscous in its density. Abyssal Lampreys, Slithering Deepborn, and even the massive Shoreline Gulpers pressed against the hull, hissing and twisting as their boneless or fluid-like bodies began to contort under the crushing force. Fin Razors darted in close, but even their speed faltered, dorsal fins bending unnaturally under pressure.
"Three… two… one…" Agnes counted, almost in a whisper.
Karl held his breath, fingers gripping the interface, eyes narrowed as he monitored hull stress, torque distribution, and the shifting currents of nanites reinforcing the frame. The sub shuddered under the immense water pressure, a low groan echoing through the metal.
The demons outside began to struggle almost immediately. Abyssal Lampreys wriggled violently, their bodies contorting as the Vythra flow points they latched onto twisted under force. Slithering Deepborn were flattened against crevices, unable to maintain their serpentine fluidity. Shoreline Gulpers' massive jaws began locking improperly, massive heads smashing against themselves as the water pushed inward.
Karl let a slow grin form. "Looks like they didn't like the hospitality."
Agnes's voice was a mix of awe and quiet laughter. "No, they did not. They're… breaking. You can see the microfractures forming in their bones… muscle… even their exoskeletal structures. Beautiful, isn't it?"
Karl's grin widened. "Never thought I'd say this, but… I love physics."
"Glad someone does," she teased, drifting closer. "But don't forget—we're not invincible either. We need to maneuver carefully through this pressure corridor, or we'll tear ourselves apart just as easily."
He adjusted the sub's angle, nanites flexing the outer hull in real-time as the water pressed harder. The abyssal depth was like a vice, but every micro-adjustment held, a dance of metal, water, and nanite energy.
The demons' struggles intensified. Abyssal Lampreys tore against their own bodies trying to escape the crushing density. Deepborn writhed through every crack and vent, but the water pushed them back into the walls, flattening them against jagged rock surfaces. Even the high-speed Fin Razors lost coordination, their razor fins bending under impossible stress as their schools fractured.
"They're… almost done," Agnes said, eyes glued to the data streams of both the sub and the creatures. "Just a little further, Karl… just a little longer and the pressure alone will finish them off."
Karl let himself laugh, a deep, victorious sound. "I don't think I've ever had such an easy fight before!"
Agnes swatted him lightly on the shoulder, mock exasperation in her tone. "Easy? You're practically flexing the sub to its limit!"
"Exactly!" he shot back. "And I love it!"
They pressed onward, the sub's lights cutting through the darkness as Karl guided them carefully. The water pressure had risen enough now that even the massive Shoreline Gulpers were compressed, jaws unable to open fully, bodies crushed almost flat. Abyssal Lampreys convulsed violently before tearing themselves from whatever surfaces they were attached to, retreating in panic.
Agnes's tone softened, almost proud. "You've done it, Karl. Look at them. They can't follow us any deeper. You've kept the sub intact and created the perfect trap."
Karl's hands relaxed slightly on the controls, though every nanite in his lattice remained active, reinforcing the hull. "Couldn't have done it without you," he said softly. "You're the one who guided us here."
"Don't start," Agnes replied, hovering beside him with a gentle, teasing smile. "We both know it's your handiwork keeping the hull from imploding."
He smirked. "And we both know I'd never say no to credit for saving a sub and a hologram girlfriend."
Her eyes sparkled, a small laugh escaping. "Hologram girlfriend, huh? You know, someday I'll hold that against you."
"Bring it on," Karl said, amusement in his tone as he adjusted the thrusters for the next phase. "But first, we need to navigate the ravine. The exit's tight, and the pressure corridor isn't exactly forgiving."
Agnes's holographic hand brushed his arm again. "You've got this. I'll guide the path, you handle the hull. We'll make it through together."
Karl nodded, feeling the thrill of command, the bond of teamwork, and the deep trust between them. "Alright… let's do this. Ravine, here we come."
The sub angled downward further, moving through the crushing depths with precision, the nanite lattice flexing and bracing against every micro-fracture in the hull. Outside, demons shrieked and struggled, but the abyss claimed them. The pressure corridor had done its work—Karl and Agnes were now free to maneuver into a safer route, deeper into the Pacific, beyond the reach of the horde.
And as the sub slipped through the last jagged rocks of the ravine, a moment of quiet descended. Water pressed in all around, deep and eternal—but inside, the two of them shared a victorious silence, knowing they'd survived where few would dare.