This has been by far my favourite chapter to write so far. Ever since I first conceived this storyline, I have been looking forward to this chapter: pitting Octavia against Aerrow in an impossible duel. This is really the culmination point of the story. I just hope I've done it justice.

"Octavia… don't!" Bellamy spoke – pleaded – from his position, shackled to the wall, unable to do anything. "You can't…" tears began forming in his eyes as he said it. He could see everything that was about to happen. Octavia was going to try to fight Aerrow. And she was going to die. Having seen what he had just done to the other black clad warriors, Bellamy knew she wouldn't stand a chance.

Octavia ignored her brother, instead staying right where she was, glaring into the emotionless blue eyes of the person that had once been Aerrow Eroxin. She saw his hands go to the hilts on the swords stowed over his back, saw him draw them slowly, coldly. Saw the glistening blood still on their blades. She closed her eyes and repeated in her head what she had said to herself every night since the day she learnt how to speak:

I am not afraid.

Eyes hard and evil, Aerrow advanced towards her slowly. She could not help but back away from his imposing form as he approached. She gripped her sword tightly, ready for what was surely to come.

"Aerrow, listen to me." She said to him, voice hard and determined, hanging on to the hope that any part of Aerrow that was left would listen. He didn't.

Quick as a flash, he swung his sword at her. She barely registered it in time, and quickly brought her own sword up to parry it.

"This isn't you!" Octavia continued, stumbling backwards from the force of the strike. She was immediately forced to block another, harder swing.

"This isn't who you are!" she shouted at him. Aerrow yelled in rage as he brought both his swords across at her, then span around and viscously kicked her away.

Propelled backwards by the kick, Octavia was unable to keep up with her momentum and tumbled to the ground. Aerrow stood over her instantly, sword in hand.

Wincing from the pain, Octavia looked up at the man that had once been Aerrow, the man she had once admired, both as a warrior and as a person. Only looking at him now, she knew that there really was nothing left. Whatever Oblivion had done to him, they had taken his soul. In the past, she would have been saddened, perhaps even distraught. But not now. Not this time. This time, it gave her determination..

Aerrow raised his sword above his head, preparing to deliver the final, killing blow.

"So this is how it ends, huh?" She growled at him, sparks of fire igniting in her eyes.

Aerrow brought the sword down.

Just as Octavia leapt into action.

She brought her sword in front of her and their two blades crashed together in reverberating fury.

Octavia never stopped moving. She was on her feet in an instant and straight away launched into the fight of her life.

If he was momentarily stunned by Octavia's fightback, Aerrow did not show it, and now swung his twin blades at her with all his enhanced skill. Octavia parried his blows doggedly, ultra focussed.

The others could only watch on in horror. Their fight was dynamic, acrobatic and brutally, savagely fast. Octavia fended off Aerrow's attacks with every ounce of strength and concentration she had. This was unlike every other fight she had ever, ever been in. This was about pure survival. But it was also about something more.

As she fought, she flashed back to everything that had happened to her. Her entire life, she had been hidden away, kept from having the life she deserved. She thought of that dreaded compartment under the floor in the Ark, where she was trapped in eternal darkness for so, so long. She thought of her fight with Fio, and how he nearly pummelled her out of existence. And finally, she thought of Aerrow, and how he refused to train her, how she wasn't good enough. This was her chance. This was her chance to prove she was good enough.

Those memories, those heartbreaks, the mental agony of her life so far, it fed her anger, gave her strength, gave her energy. And so Octavia fought on, doing something Sai Rakira and the Qinta had not been able to do: she survived

Her blade continued to clash with Aerrow's, ever building in intensity. But she never faltered. Not one attack was misplaced. Not one block was inaccurate. She made not one single mistake, for she knew a mistake would mean her death, and death of everyone else she cared about.

Right then and there, in that room deep within the Earth itself, Octavia felt something change. Her sword felt as if it was an extension of her arm. Her senses blurred together, all perfectly attuned to her surroundings. Time seemed to slow for her as was able to crystal clearly her opponents next move. In that moment, she became more than just an ordinary girl. She became a warrior.

The others watched on in a mixture of shock and amazement, at what was happening and that Octavia had survived this long. But it couldn't last.

With a scream pure fury and effort, Aerrow cleaved right through Octavia's sword with a brutal swing. Octavia looked down in shock as the blade of her weapon clattered to the ground, useless. And then Aerrow ploughed into her with unbelievable force, driving her backwards and shoving her hard against the wall.

His swords crossed over the front of her throat, pinning her to the wall. She could feel the razor edge of the Coandite biting into her skin. She looked dead into the Aerrow's eyes. They were utterly blank and lifeless. In a moment of crushing realisation, she finally realised Aerrow wasn't there, and no matter how hard she tried, there was no getting him back. In that moment, she stopped fighting.

"What have you become?" she whispered in anguish. She closed her eyes and waited for the slicing that would bring about her death. It didn't come.

She opened her eyes and saw Aerrow still staring at her, just as fiercely, but completely still.

And then he spoke.

"There is a madness inside us all." His voice was quiet and raspy, yet incredibly intense. "A madness that lurks in our deepest animal minds, yearning, begging to be set free at every moment of our lives. A madness which is sedated into paralytic silence by the tyranny of identity."

He paused, and looked deep into her eyes, and Octavia saw something there. Something different, amongst all the anger, all the rage.

She saw sadness.

"I am that madness." Aerrow growled, snapping back to reality, slicing his swords across Octavia's throat.

But Octavia moved faster. She brought her leg up, kneeing him in the midriff, while simultaneously punching him in the temple and freeing herself from his deathlock. As she did so, she yanked one of his swords from his grip.

Once he recovered, Aerrow stood and faced Octavia once more. This time, they both had only one, identical weapon each. And then they re-engaged again.

This time, both warriors were fatigued. What had once been smooth, precise swings were now laboured and sloppy. Reactions were slower, and more swings missed their targets. Aerrow though, with his enhanced endurance, easily outlasted Octavia, and began taking control of the fight, landing more and more hits to his fatigued opponent. Octavia did all she could to avoid his strikes as she began backing away. She winced in pain as he sliced across her cheek, drawing blood, just as she felt the cold rock of the wall against her back. He had her trapped.

Octavia saw Aerrow advancing towards her, saw what he was about to do. She knew this was her only chance now, so just as Aerrow was about to strike her down, she attacked.

She spun around… twirling her sword behind her back… completing the spin, she swang at him, causing him to jump backwards… spinning again, she kicked him backwards… She brought herself back around to face him, jabbed her sword at him and…

Struck him.

Clean through the right shoulder.

Aerrow shouted out in pain as Octavia spun him around so his back was against the wall, and kicked him. Hard.

Defeated, Aerrow slumped to the ground. Octavia stood over him, his sword in her hand. Staring at him, she smiled internally. She had used his own special attack against him. And this time, it had worked…

The whole room was stunned. No one had been expecting that to happen.

"You are not invincible." Octavia growled at him.

Aerrow looked up at her, eyes alight with fury. Without even flinching, he coldly yanked the sword out of his shoulder and began getting back to his feet.

Suddenly though, a streak of black and white raced up Octavia's leg and crawled onto her shoulder: Cleo.

The Lace Monitor immediately leapt onto Aerrow's chest – her weight forcing him back to the ground – and then she bit him on the neck.

Aerrow yelled in pain, and tried to yank the Lizard off of him, But Cleo held firm in her grip, more and more her venom laced saliva trickling into Aerrow's bloodstream with every passing second.

And then something strange happened. After about thirty seconds, Aerrow let go of the Lizard and instead clutched his head and screamed.

Octavia took a step back in shock as Aerrow writhed on the ground in utter agony, clutching at his head, throwing Cleo off him.

The Lizard quickly took its place back on Octavia's shoulder just as Aerrow's convulsions stopped. He looked up at her, and she saw the anger, the ignorance, soullessness leaving his eyes. A tear trickled slowly down his cheek as he stared blankly up at the cieling and weakly choked out "So… nearly… free…"

Then he closed his eyes slowly and lapsed into unconsciousness.

The sword dropped from Octavia's hand as she took several small, shaky steps backwards, closed her eyes and exhaled in deep, deep relief. She had done it! She had defeated Aerrow in combat. She had succeeded where the legendary Qinta warriors had failed. She had saved her friends.

That thought snapped her back to reality, and she instantly grabbed a set of keys from one of the dead soldiers and set about freeing her friends.

She went straight for her brother first. No sooner had she released him from his shackles that he wrapped his arms around her and hugged her tightly. Octavia returned the embrace, silently confiding her lingering emotions from the fight with the person she cared about most. It was a long time before they separated and working together, they freed the rest of their people.

Clarke sighed in total relief as she felt her weight transfer back into her feet. The first thing she did was rush over to Raven and release the mechanic from her restraints. The events of that day had not yet fully caught up to her. Everything seemed to go by in a rush, and she felt as if she was on autopilot as she hurried to free the remaining delinquents.

Suddenly, she heard the sound of the metal door beginning to rise, and her eyes hardened instantly as she remembered. She quickly grabbed a P90 rifle off the ground and span around, pointing its barrel at the person who had opened the door.

Hans Van Dyke froze instantly when he heard the sound of a safety catch being clicked off. Slowly, he turned around with his hands in the air and faced Clarke and the other furious prisoners. Strangely, he did not look frightened at all.

Clarke glared at the old scientist. She glanced at the person that had once been Aerrow – still slumped unconscious against the wall where Octavia felled him – and then snapped her glare back to Van Dyke. "You turned Aerrow into that monster." She growled. "You're going to pay for that."

Van Dyke grinned slyly at her. "You're not going to kill me." He said, voice eerily calm and confident.

"Want to bet?" Clarke hissed, before seamlessly jamming her finger down on the trigger.

The P90 instantly spewed forth a devastating barrage of machine gun fire. The hypervelocity bullets slammed into Van Dyke's chest, throwing the old man completely off his feet and propelling him backwards through the open door.

It was a full 3 seconds before Clarke let go of the trigger. Eyes completely free of remorse, she stared at Van Dyke's mangled body. Even in his final moments before death, he still seemed totally pleased with himself. "Bad move." He spluttered.

"Why is that?" Bellamy growled.

Van Dyke smiled evilly at him. "The Earth is no ones to rule. With my death, comes yours." With that, Hans Van Dyke, scientist, geneticist, head of Oblivion, breathed his last.

No sooner had his heart stopped beating, that an incessant beeping noise could be heard. Curious and confused, Bellamy edged forward cautiously, and flipped back Van Dyke's outer coat, revealing a small transmitter, it's red light blinking furiously. "What the hell…" Bellamy breathed.

Suddenly, a blaring alarm sounded throughout the corridors of the mountain. The entire group looked around frantically, wondering what was going on.

And then an automated announcement was made.

'Facility compromised. Erasing procedures initialised. Nuclear detonation in T-minus 5 minutes and counting.'

It took Bellamy a few seconds to comprehend what has going on, but then he understood, and he felt his blood run cold.

They were going to blow it up. Somehow, a transmitter had been wired into Van Dyke's body that at the moment of his death had trigged a self destruct mechanism. A nuclear self destruct mechanism. The old scientist had had a plan right until the end. And now, unless they could get out of the Mountain in less than five minutes, they were all going to be annihilated.

"Clarke, we need to move now!" he shouted. The others realised what was happening too, and everyone began rushing towards the exit, under the direction of Octavia, Jasper and Kane.

Clarke and Bellamy lingered behind for a moment. Clarke stared despondently at Aerrow's body.

"What do we do with him?" Bellamy asked quietly.

Clarke took a shaky breath in as memories of everything Aerrow had been flooded her mind. "We leave him here." She said in resignation, "There's nothing left of him anymore."

With that, they left the room, leaving Aerrow to be blown up.

…

They raced through the corridors under the guidance of Bellamy, who knew exactly which way to go thanks to his time on the inside.

All around them, the alarm kept blaring as they moved up through the levels. By now there was only three minutes left until detonation.

They rounded a corner and there, gloriously, was the main door. The group rushed as one towards it, but then stopped in their tracks instantly when a single figure walked out in front of them: Abby Griffin.

"Abby?" Kane said in shock. "Where have you been? What are you doing here?"

Abby kept her expression stern and completely neutral as she slowly raised a pistol and levelled it a Kane's head. "I'm sorry, Marcus." She said coldly, "But I'm afraid I can't let you leave."

Her words cut through the group like an axe, ripping their souls and their beliefs right out of them. No one could believe it. Abby was… one of the bad guys?

Bellamy was more focussed on the gun in her hands. He looked at the transmitter he had taken from Van Dyke. Its display read two minutes. Two minutes until detonation.

Clarke's eyes hardened instantly the moment she saw her mother again, remembering what she had done. She led Oblivion to Aerrow, let them take him away, let them take the warrior he was, rip his soul out and replace it with evil. She would never forgive her for that.

She strode slowly out in front of the group, and looked dead into her mother's eyes. Abby saw her daughter, and in that moment, her eyes were filled with a deep regret.

Clarke glared at her mother. "You let them take him." She growled, "You led them right to him. Why?"

Abby held her daughters stare. "Clarke, there are things in this world that you don't yet understand-"

"I don't understand how you can turn on your own people!" Clarke shouted through tears, "How you can serve us up like Lab Rats to be slaughtered!"

Bellamy clenched his fist. One minute left. In sixty seconds, they were all going to be vaporised, and Abby was preventing them from leaving. He had to do something, and fast.

"Clarke, listen to me." Abby said slowly, yet seriously. "Everything I have done, has been because I care about you. Because I want a better world for you to live in. Because-"

Bellamy charged at her from the side, crashing into her and knocking the pistol from her grip.

Fifty seconds left.

Bellamy and Abby rolled on the ground, struggling to overpower each other. The much stronger Bellamy quickly got the upper hand and pinned her to the ground.

Forty seconds left.

Suddenly though, Abby kneed him in his side, throwing him off her. She quickly got to her feet and pulled a second pistol from her vest. She aimed it squarely at Bellamy's head. He was on his hands and knees, totally defenceless.

"I'm sorry it had to be this way." She told Bellamy in an icy tone. She made to pull the trigger.

But then she got shot.

Thirty seconds left.

The bullet hit Abby directly between the eyes. Time seemed to freeze. Abby stood completely still for a moment, before dropping to the ground, killed instantly.

Everyone was silent as they beheld the scene in front of them. Abby Griffin lay still on the floor on Mount Weather, blood running from the gunshot wound in her forehead, her face an expression of total, utter shock.

Her shooter: Clarke Griffin.

Smoke still emanating from the barrel, Clarke slowly lowered the pistol and took a shaky breath. She'd had no time to think about what she was doing. She had simply snatched Abby's fallen pistol from the ground, taken aim, and fired.

And now her mother was dead.

She had no time to realise what she had just done. She only had one thought: survive

She quickly tossed the pistol to the side and raced towards the door.

Twenty seconds left.

Clarke grabbed the heavy flywheel sealing the door shut and pulled with all her strength, but it would not budge. David and Nathan Miller quickly joined her, along with Kane, Wick and Monty, and together, they slowly heaved the flywheel around and the door creaked open.

Ten seconds left.

Clarke shouted desperately for everyone to leave. The group poured out of the door and began sprinting for their lives.

Five seconds left.

Clarke took a final, sad look inside the Mountain, thinking of all the lives that had been lost, all the people she loved that had been killed in this war, before the slammed the button to close the door, and took off after the others

Four seconds left.

Everyone ran as fast as their legs could possibly carry them, desperate to escape the blast. Clarke had no idea how much time was left, nor how big the explosion was going to be. All she could do was run, and hope to god the Mountain would contain the blast.

Three…

Two…

One…

Detonation.

Deep inside Mount Weather, the 97 year old Nuclear warhead – sitting, undisturbed since the apocalypse – suddenly roared into life, unleashing its fury in the form of a devastating, white hot inferno.

Everything inside the Mountain was vaporised instantly, from the bodies of the Mountain men, to the Qinta, to the entire Oblivion organisation. Along with Hans Van Dyke, Abby Griffin, and Aerrow Eroxin. Nothing survived.

Outside, Clarke and the others felt the ground rumble, before a deep booming sound was word. A split second later, they were propelled off their feet by the shockwave of the blast.

Clarke was thrown forwards, and slammed into a tree. She fell to the ground and lay there, her entire body screaming in agony. Her head throbbed, her ears were ringing, but she was alive.

Somehow, she and the rest had survived the devastation of the nuclear explosion. She got shakily back to her feet just as an almighty crashing sound was heard. She span around as Mount Weather, once an imposing, impenetrable feature of the landscape itself, collapsed in on itself and began burning itself into eternity.