He braced himself as the smoke creature reached out and like its namesake it curled round the Doctor and began to fill his nostrils and his mouth.
He tried not to choke as the taste was vile, like being forced to drink bitumen. He forced himself to relax, knowing that he had to do this to make his plan work.
He shuddered when he felt the real creature touch his mind... it was so powerful...so old and so hungry but still he let it invade him.
Just a little bit more, he said to himself...that's it, take the bait.
He reached out with the part of his mind that was still free of the creature. He could sense that the trio were out in the open, but still in danger. He had to hold on...wait, the Darkness, it was still inside. Maybe he could...if he could hold out for long enough.
If he touched the power of the creature, just for a second...perhaps he could. He reached out and touched the edges of it. He nearly recoiled when he touched it, now he knew for certain it had to be destroyed; it was like touching hell itself.
A movement caught his eye and without thinking he caught the figure that emerged from its hiding place with a flick of his eyes.
"Going somewhere?" he asked.
The Darkness had hid himself, waiting for the right moment to run. It had heard snatches of the conversation and had decided to take his chance. Better to have an army of Daleks than be a meal, and the sooner he could ditch this human female, the better.
He took his chance whilst the creature was pre-occupied with the Time Lord...well he thought he would.
He'd only gone a few paces when he felt an unseen hand stop him. He panicked and tried to move back, but was dragged forward until he was facing the Time Lord but not quite the Time Lord.
He'd wanted control of the Time Lord once the power had been contained inside him, but not this.
"Going somewhere?" a voice that was definitely the Time Lord's asked him.
Summoning the courage from somewhere the Darkness replied. "I was going to stop them escaping."
His answer earned him a raised eyebrow and now empty black eyes boring into his host's as if looking for something.
The Doctor drew more of the creature's power, knowing it was shorten the time he had left and looked into Gwen's eyes and deeper into her mind, hoping for... yes there, a glimmer of hope.
He didn't have much time, he knew that now. He could feel his consciousness fading and slipping away. If he could free Gwen from her prison then he could let go happily and with a free conscience.
He searched through her mind for the Darkness and found him, cowering in the deepest recess and drawing more of the creature into him, he latched onto him.
"You've created hell for billions and I didn't fight back. For that I deserve whatever hell is reserved for me. But you, you deserve whatever hell this thing came from."
With the last of his mental strength he grabbed hold of the Darkness and pulled him from Gwen's mind, closing himself off the screams of pain from her as he ripped the Darkness from her.
As he felt her collapse he released a little of the power from the creature, just enough to keep her conscious and held her as she came round.
Gwen felt like she'd been trapped in molasses and opened her eyes and looked straight into golden brown ones.
She tried to struggle but was held fast. A voice, soft and filled with sadness whispered to her.
"It's alright, you're safe," the voice said and released the hold it had on her.
She stepped away, fear written on her face, but it faded when she saw the pain scribed across the face of her rescuer.
"Go!" he gasped. "I can't...much longer!"
"I'm sorry," she said and turned away and hurried up the steps that were beginning to crack. She tried not to here the scream of agony that echoed after her.
His words were cut off by his own scream...no, not yet, he hadn't finished...they needed to be safe...he had to hold on...one more thing.
Jack and Martha stumbled out of the tunnel into the brightness of the city and into a battle. In the time they had been inside the chamber the battle between the Daleks and the Immortals had moved into the square that led to the steps.
Both sides were vastly depleted and there seemed to be more Daleks in the sky and the Immortals were losing the battle through sheer force of numbers.
As they stumbled into the light, several Daleks turned in their direction and they froze, knowing that death was their only fate.
Then they heard it, the most wonderful and miraculous sound in the universe. Their hearts soared as a familiar blue wooden shape began to coalesce in front of them.
The TARDIS materialised quicker than it usually did and the doors were open.
Spurred on by the miracle Jack dragged and pushed Martha and Ianto ahead of him and shoved them through the open door and expected them to close behind them; but they didn't and then he saw why.
Another miracle appeared in the form of Gwen emerging from the tunnel, he face set in grim determination.
Jack's hand went to his sidearm but as Gwen came closer he could see she was pale but it looked like her as she barrelled into the TARDIS.
It had to be her? Why else would the TARDIS let her in?
The answer was forthcoming as the doors began to shut behind her and the sound of the engines filled the air.
Jack made a decision in the seconds between and dived out of the door.
"Jack!" Martha screamed as he squeezed through the gap just before the doors shut and the TARDIS began to dematerialise.
"Don't you dare!" she yelled, knowing the TARDIS was doing what the Doctor had programmed her to do. "You take us back!"
The rumble she got in returned sounded like a refusal, so she began pulling every lever and hitting every button.
She let out a frustrated scream when the TARDIS refused to budge from its course.
"Take us back!" she sobbed and sank to the floor beside a still shocked Gwen and Ianto.
"You can't leave them...you can't."
She felt the TARDIS shudder and there was change in the sound of the engine.
"Thank you," she said and wiped a tear from her eyes.
Deep inside the TARDIS her huge heart heaved, torn as she was between obeying her Time Lord and doing what Martha begged.
She made a decision and knew her pilot may never forgive her and changed course.
She couldn't let him die, not like this...she loved him too much.
The Doctor could hear himself screaming as the power of the creature burnt through his body.
He'd felt the TARDIS and was glad that they would be safe, now he could let go and end this.
He could hear the Darkness screaming along with him and that made him happy; at least he would be taken it with him as well as the creature. He'd had a glimpse of the hell the creature had come from and he knew it would be nothing short of an eternity of pain and torture...but that was fine.
He knew when he triggered the trap he'd set it would take the city, the temple and anything that was on the ground with him...all there to torment him in hell.
He steeled himself and with what was left of his own mind he closed trap around the creature and with an almighty effort began expelling it from himself.
The pain was beyond anything he'd felt as once again that taste of bitumen filled his mouth and black smoke began to pour from his mouth and began to coalesce as the creature again.
It howled as it felt itself being torn apart and the Doctor felt the ground beneath him shift...it was beginning.
With a sigh he finally let go and sank to floor, feeling everything that was him slip away, never noticing the figure that emerged from the falling rubble and dust into the chamber.
Jack burst out of the tunnel as the ground began to shift and dodged pieces of falling masonry.
He's heard the agonised scream and that had spurred him to even greater speed. He was however stopped in his tracks when he saw the figure crumpled on the floor and the floor cracking around it.
"No!" he cried and sprinted over to the figure and grabbed hold of the collar of the Doctor's coat and dragged him away.
He tried not to look at what the crumbling floor was revealing; he didn't want to know. He turned the Doctor over and his heart nearly stopped when he realised there was no sign of life.
"No, not this time," he said and placed his mouth against the Doctor's mouth and breathed his life essence into him.
The Doctor heaved under him but once again became lifeless. Jack tried again but there was no response...the Doctor was gone.
The ground shifted under him and the hole that was a few feet away from him began to expand, revealing more of what lay underneath.
Jack looked down at the still dead Time Lord and smiled sadly. "At least we'll be together," he said quietly and gathered the Doctor's body in a protective if useless embrace.
Then he heard it, that miraculous sound and the shape of that wonderful blue box as it began to form.
The door was flung open and many pairs of hands grabbed Jack and the Doctor and hauled them into the still coalescing TARDIS, the doors slamming behind them and fading away before it had solidified.
As it faded the floor vanished in a sea of fire and the screams of something that knew it was going to hell.
The ground around the hidden chamber began collapsing in on itself and the hole began spreading, reaching out to the two armies still fighting and swallowed them with the ease of a shark swallowing a minnow.
The Daleks that remained in the air halted, unsure of what to do. Then the call came, a familiar voice, one that they were programmed to obey.
"My Daleks, return to me. Return to your Creator."
"We obey!" they chorused and turned away as the city below began to disappear and turn into a lake of fiery destruction.
Jack took in a huge gasp of air as he realised he was safe within the TARDIS and was elated when the Doctor suddenly heaved under him.
He began to laugh...the joy of escaping what was certain death and getting everybody back. But most of all he had his Doctor back, a little battered but alive.
He looked down at the Doctor and his laughter was cut short at the look of confusion on the Time Lord's face.
He wasn't prepared for the cry of terror that preceded the Doctor wrenching himself from Jack's grip and scrabbling to the edge of the platform.
"Doctor?" he said softly.
The others had now taken notice and were staring at the Doctor too.
The Doctor's reaction was a shock to them all. "Where the hell am I, and who the hell are you!"
Before anyone had a chance to take in the words or form a reply the TARDIS lurched and the sound that came from deep within sounded like a wounded animal and lurched again.
Jack ripped his eyes away from the still terrified Doctor and managed to haul himself upright as the TARDIS lurched again. He tried to close his ears to the sound coming from below and the demands of the Doctor and looked at the screen.
His eyes widened in shock...they were on course for Earth...but they were out of control.
"We're going to crash!" he yelled
Everybody bar the Doctor grabbed hold of something for support and closed their eyes.
That awful sound filled the TARDIS and the impact as it hit threw the occupants around like tumbleweed in the wind and they were plunged into darkness.
Jack was the first to come round and coughed as his lungs filled with acrid smoke. The whole chamber was bathed in a sickly green glow. He could see the others were stirring and began looking for the Doctor and began to panic when he couldn't see him.
Then an awful thought struck him and he looked over at the doors.
They were wide open...the Doctor was gone!
He stumbled out into the rain and away from whatever the thing was he'd found himself in...away from the group of people he didn't know.
He never looked back, he just ran, not stopping until his body screamed at him to stop. He looked round and spotted what looked like shelter.
He crawled underneath the pile of wood and metal and huddled into one corner.
He was cold, bleeding and very frightened...where was he and who the hell was he?
TBC in 'Inaestimabilis proprietas (Priceless Property)'