His Fatal Mistake, My Sweet Revenge

Trapped 3,000 meters beneath the sea, the submersible I designed was my coffin. The air was turning to poison.

But my fiancé, Jeffery, gave our only long-term life support-a CO2 scrubber I invented-to his social media star mistress.

"You're strong, Elaina," he said. "You can figure something out."

When I tried to use the emergency comms, he broke my wrist and smashed the console.

He and his mistress sealed the hatch, leaving me to die alone in the crushing dark.

He chose his career over my life. He chose her over me. The man I was supposed to marry would rather I suffocate at the bottom of the ocean than face a failed mission.

But as the blackness closed in, I remembered a secret. A tiny, personal emergency pinger I' d built into my glove. With my last bit of strength, I tore the seam with my teeth and slammed my hand against my head. A faint click echoed in the silence. My revenge had just begun.

Chapter 1

Elaina Valencia POV:

The world was ending, not with a bang, but with a slow, suffocating hiss. I knew it. Every cell in my body screamed it.

My breath hitched, a desperate plea for air that the failing environmental system of the submersible couldn't grant. The cold seeped into my bones, a deep, pervasive chill that promised to turn my very blood to ice.

I was trapped, 3,000 meters beneath the surface, in a crippled steel coffin.

The pressure outside was immense, enough to crush a battleship into scrap in seconds. Inside, my own body was starting to fail.

My fingers, numb and clumsy, fumbled at the console. Hypoxia was setting in, painting the edges of my vision with shimmering light.

As a marine biologist and robotics engineer, I understood the mechanics of my impending death with chilling clarity. It wasn't just the failing life support; it was the betrayal that pulsed beneath it, a toxic current in the frigid darkness.

I needed the scrubber. My proprietary CO2 scrubber. It was our only long-term chance.

My gaze snapped to the compartment where it should have been. My hands, trembling, reached for it.

The compartment was empty.

My breath caught. No. It couldn't be. Not now.

A cold dread, colder than the abyss outside, clutched at my chest. The scrubber was unique, a prototype designed for extended deep-sea missions. It could have given us days, maybe even a week.

"Jeffery!" My voice, raw and raspy, cut through the oppressive silence of the damaged sub.

Jeffery Castillo, my fiancé, turned from where he was trying to reassure Jaden Savage. His eyes, usually so quick to meet mine, darted away.

He looked guilty. He looked shifty.

"What is it, Elaina? Keep your voice down. You'll upset Jaden." He spoke in his publicist's calm, measured tone, as if we were discussing funding, not fighting for our lives.

My blood ran cold. "The scrubber, Jeffery. Where is it?"

He hesitated, a fleeting shadow crossing his face. "It's... it's fine. We have plenty of air."

"Don't lie to me." My voice was a low growl, laced with a desperation I couldn't hide. "The telemetry shows critical oxygen levels. The backup failed. We need the primary scrubber. Now."

He swallowed hard, his gaze shifting to Jaden, who was huddled, trembling, in the corner, her face a mask of manufactured fear. "I... I gave it to Jaden."

The words hit me like a physical blow. The air rushed out of my lungs. I swayed, bracing myself against the console.

"You what?" My voice was barely a whisper. It felt like the pressure outside was crushing my very soul.

"She was panicking!" He gestured wildly towards Jaden. "She's not used to this. She's delicate. You're strong, Elaina. You're the engineer. You can figure something out."

Jaden looked up, her eyes wide and innocent, but a flicker of triumph danced within them. My scrubber, strapped awkwardly to her chest, pulsed faintly, filtering the toxic CO2.

Fury, cold and precise, replaced the panic. "That scrubber was designed for us, Jeffery. For the crew. It's life support, not a comfort blanket for your social media star."

"Don't be so dramatic." He scoffed, his face hardening. "We're fine. Just think, Elaina. Invent something. You always do." He turned back to Jaden, patting her hand. "See? I told you she'd be okay. She's brilliant."

Jaden offered a weak, grateful smile, her eyes still fixed on me. A challenge. A sneer.

"Jaden Savage is a social media influencer," I ground out, my voice thick with disbelief. "She was brought on this expedition for publicity, not for her deep-sea survival skills. You gave away our only chance because you wanted to look good for her."

"She's a documentarian, Elaina!" Jeffery snapped, his face flushing. "She's bringing our work to the world! Without her, where would our funding be? Where would my career be?"

"Your career? Jeffery, we are dying down here!" I pointed to the flickering lights, the groaning metal. "This submersible, this expedition, it's all my design, my research! I know what's happening. The structural integrity is compromised. We have hours, maybe less, before the next tremor collapses this cave entirely. That scrubber was our only chance to buy enough time for rescue!"

"Stop being so hysterical!" He recoiled as if I'd struck him. "You're scaring Jaden. This is why no one trusts you, Elaina. Always so intense, so obsessed with your work. You can't just relax, can you? You always have to be the smartest person in the room."

His words, sharp and venomous, pierced through the fog of hypoxia. They were words I' d heard before, echoing from his sister, Carlene.

"Intense? Obsessed?" I laughed, a harsh, humorless sound that scraped my throat. "My 'obsession' is what keeps us alive, Jeffery. It's what built this sub, what designed that scrubber. It's what makes this mission possible! What makes your job possible!"

"It makes you difficult!" He retorted, his voice rising. "It makes you unapproachable. No wonder you're so lonely, Elaina. You push everyone away with your 'genius.' Jaden, at least, is grateful." He looked at Jaden, a soft, almost tender expression on his face. "She appreciates what I do for her."

The cold truth of his words settled over me, heavy and suffocating. This wasn't just about a scrubber. This was about years of simmering resentment, of his insecurity festering beneath his charm. He hadn't just accidentally betrayed me. He had chosen to.

"This is over, Jeffery." My voice was flat, devoid of emotion. "Us. This. Everything."

He stared at me, dumbfounded. "What are you talking about?"

"I'm talking about survival." I ignored him, my gaze sweeping over the console, searching for the emergency comms. "I'm calling for help."

My fingers flew over the controls, adrenaline momentarily cutting through the haze. A faint hum, a spark of hope.

But Jeffery was faster. He lunged, his hand slamming down on mine, twisting my wrist. A sharp crack echoed in the confined space. Pain exploded, blinding me for a split second.

"No!" He hissed, his eyes wild. "You can't! This mission cannot be a failure! My career, my family's reputation... This can't get out!"

"You'd rather we die than face a failed mission?" I gasped, clutching my throbbing wrist.

"It's not a failure if we handle it correctly." His voice was low, menacing. "You're panicking. You're unstable. I'll report that. Jaden will back me up. We'll say you went hysterical, damaged the comms yourself. It's for the best, Elaina. For everyone."

He ripped the damaged emergency beacon from the console, its wires tearing with a sickening snap. He held it up, a twisted parody of a trophy.

"Don't even think about it," he warned, his voice laced with venom.

My head swam. The pain in my wrist, the lack of oxygen, the crushing weight of his betrayal. My body felt heavy, almost liquid.

Jaden, seeing my weakening state, emerged from her corner. She approached, a slow, predatory smile spreading across her lips. In her hands, she held the CO2 scrubber, almost cradling it.

"Poor Elaina," she cooed, her voice dripping with fake sympathy. "You're just not strong enough for the deep sea, are you? It's okay. Jeffery will take care of me. He always does."

A wave of impotent rage washed over me, but it was quickly swallowed by the crushing despair. I crumpled to the floor, my vision tunneling.

"Jeffery..." I choked out, a final, desperate plea. "Please..."

"Be strong, Elaina." He didn't even look at me. His gaze was fixed on Jaden, a soft, indulgent smile playing on his lips. "You're a genius. You'll figure it out. You always do."

He turned back to Jaden, his arm wrapping around her. They were leaving me. They were leaving me to die.

"Are you... abandoning me?" My voice was just a whisper, lost in the hum of the failing systems.

He paused, then turned, his face devoid of emotion. "It's for the best, Elaina. You're not thinking clearly. Just rest. We'll... we'll send help when we can." He offered a weak, unconvincing smile. "Just keep breathing, okay?"

Jaden stepped forward, her eyes glinting with malicious amusement. "Don't worry, Elaina. We'll make sure your legacy lives on. Jeffery will tell everyone about your brilliant designs." Her hand, clad in a sleek, designer glove, held up the CO2 scrubber. "It's actually quite comfortable. Thank you."

The last flicker of hope died. My eyes fell on the scrubber in Jaden's hand. If I could just...

With a surge of primal instinct, I lunged, a desperate, pathetic attempt to reclaim my life. My fingers, still numb, brushed against the device.

Jeffery, seeing my movement, turned sharply. His foot lashed out, connecting with my head with a sickening thud. The world exploded in a kaleidoscope of pain and fading light.

"Stay down, Elaina!" he roared, his face contorted with anger. "You're out of control!"

Jaden shrieked, a theatrical display of fear. "She's trying to hurt us! She's crazy!"

"See?" Jeffery snarled, glaring down at my prone form. "I knew it. Always the drama. Always making things about you."

My ears buzzed. The cold, the pain, the darkness. It was all a swirling vortex. I could barely hear his words now, muffled and distorted.

"We have to go," he said, his voice distant. "Before she damages anything else."

Through my blurring vision, I saw Jaden smile, a triumphant, cold smile. She held up the damaged emergency comms unit, then dropped it to the ground, stomping on it with her heel. A brittle crunch.

"Such a shame," she purred, her voice sweet and poisonous. "She was just so... difficult."

The last thing I heard before the black consumed me was the faint click of the submersible's internal hatch closing, sealing me in.