Back when the Final Wave hit, Londonders had fled to the Tube tunnels in droves, remembering their use as air raid shelters during WW2, but they would soon come to realise that the Greys were a different kind of monster than that which had threatened us before and their invasion was not to be restricted to the skies over London. The tunnels had become a death-trap. A grave for those who had believed the tunnels would protect them from the terrifying crafts that had descended upon the city, blotting out the sun and darkening the entire landscape.

I couldn't help but think of that now as I stood with my back against the platform edge, the heat of too many people on the tracks making it feel hard to breathe. Tom stood next to me, and for once, I was grateful for his presence, and for the brush of his elbow against mine.

Having reluctantly led Levi and his crew to the tunnel opening, the alarm had been sounded by Lenny and his son Lewis, who had been on watch duty, and soon everyone had come storming onto the platform. I'd hated seeing the look on their faces. Fear. Panic. Momentary relief at seeing Tom and I, only to have it replaced by anger and hurt, as if we had betrayed them by bringing Levi right into our base, even though he'd already done a pretty good job of finding it himself.

Levi's assurance that he'd happened to stumble upon us in the tunnels had done little to ease my guilt, but guilt appeared to be the one coat I wore so well now. I leaned in closer to Tom and loosely linked my fingers with his.

'There's some small irony in you admonishing us for trespassing in your Quadrant, Levi, and yet here you all are, trespassing in ours.' Taj stood on the platform, his hair loose for a change, clearly having been rudely disturbed from rest by Levi's arrival. 'What's stopping us from cutting you all down here?'

Levi appeared unmoved by the threat, and instead, shrugged his broad shoulders and sniffed at the air. 'You could do that, my man,' he said, his deep voice rumbling. 'However, the chances of you carrying out your threat, without losing a fair few of your own in the process, is pretty damn near slim, wouldn't you say? And, we come, not with malice or intent to do you harm, but with our arms open wide and our hearts ready to receive you all as comrades in this endless war. So, you tell me, what would you benefit from turning this place into a battleground?'

'You come fully-armed,' said Taj, 'and you expect us to believe that you didn't come here with intent to do harm?'

Levi broke into one of his wide, mad smiles. The laughter that seemed to come from deep within the confines of his huge barrel-like chest, was neither warm nor comforting and the hair prickled on the back of my neck to hear it.

'Excuse me, but the last time I checked, it's a warzone up there.' He pointed one huge thick finger up at the rounded ceiling of the tunnel. 'We are armed because our world is not our own anymore. Did you expect us to come here without means to protect ourselves from the monsters that now roam our streets?'

I took a sidelong glance at Tom, noting how his cheek muscles twitched as he swallowed, never taking his eyes off Levi, even though he knew I was looking at him.

Taj stepped to the edge of the platform. 'With respect, Levi, we didn't expect you to come here at all. If you come with open arms, as you say, ready to talk, then we could have arranged a more neutral place at a more convenient time for us all.'

'And yet where is neutral in this New World of ours and when is time ever convenient anymore?' Levi replied, moved closer to the platform edge, looking up at Taj with solemn, dark eyes. 'No, my man, there is no neutral and there is no convenience. There is only chance and opportunity, negotiation and transaction.'

Turning his attention on us, his gaze swept over me and rested on Tom and I saw appraisal in his eyes, a brief glimmer of something that verged on respect, tinged with the same wariness with which he viewed everyone.

'You talk a good talk, husband of Eve. Almost sermon-like in its power. Tell me, what did you do, before the world came to an end?'

My heart pounded a little harder in my chest.

'I was a teacher,' Tom replied, with no hesitation, his expression calm. 'I worked mostly in inner city schools. KS3 level and above. English was my main subject.'

'Inner city schools? Ever spend any time in Hackney?'

'I did my training in Hackney.'

Levi raised a brow and pursed his lips as he nodded slowly. 'Well, that explains everything. If you cut your teeth in Hackney, it's no wonder you've survived so long since our enemies from above descended upon us in all their righteous glory. I used to run a boxing club down Hackney way. Mean kids. Tough kids. Poor-as-fuck kids. You gotta have something special to get through to young people like that. You gotta have gumption, you know? And a way to get inside here.' He tapped his index finger against his temple. 'Let me tell you, husband of Eve, you definitely have a way of getting inside. You get right under the skin, don't you?'

I stared at Levi, barely daring to breathe.

Did he know the truth? How?

The tunnel walls swelled inwards, pushing the air out, restricting space. Everyone felt closer now, crowded in together. Claustrophobia tugged on my lungs. Weakened my bones.

Levi clapped his hands together, the sound echoing like a thunderclap in enclosed space. I flinched and felt Tom grab my hand to steady me. He squeezed, but I could do nothing but stare wildly at Levi and feel the floor crumbling away beneath me with each agonising second.

'You know, I hate a preacher, Taj, my dear mother made sure of that, but I do love a teacher. Especially one that speaks as well as young Thomas here. That's what the world needed, in my opinion. Less religion. Less sanctimonious clergymen fooling the ignorant masses. More damn good teachers that'll lift the less privileged out of the gutter and raise them up to great heights. Life is all about potential, don't you think? What can you achieve if you put your mind to it?'

Levi grinned, and I could see a gold tooth glinting at the back of his mouth.

'What can we achieve, if we put our collective minds to it? What can we achieve, if we put our collective bodies to it? An army, I say. A resistance! Potential, Taj. Potential.'

Taj looked bemused – wary, but with that same dumbfounded expression that Levi's skewed rants often evoked in people. He scratched at his head and snagged his long, dark hair behind one ear.

'Levi, do I take this to mean that you want to be a part of our plan to raid the harvesting facility in Central Hall?' he said.

Levi's face lit up, in so much as a face as often menacing as his was able to light up. 'You asked for our help, and here we are, offering our assistance. I don't mind admitting, your man here got under my skin. Buried himself right inside my head. It would be remiss of me to not assist you all in your hour of need. And besides, call me crazy, but I do love a good riot when you're on the right side and I am about ready to raise Hell inside that Black Zone.'

He was crazy. There was no doubt about that. He had to be batshit crazy to be remotely excited about going into the Black Zone, but he didn't know the truth. Tom and I weren't about to be thrown to the wolves, after all. I took a breath and leant back against the platform, feeling the stone mould into my shoulderblades.

I felt a foot nudge my shoulder and I glanced up to see Jace standing just beside me on the platform. He didn't look at me, but there was a small smile on his lips and a notable gleam in his eye. He wanted the battle. He wanted the thrill of the fight and everything that came with it and he believed Levi was here to offer just that. Maybe he was batshit crazy too. Maybe we all were for even going along with this whole thing.

My gaze switched to Taj, who was still watching Levi carefully. There was no sense of anticipation emanating from him. No emotion. No smiles. He nodded perfunctorily. And waited.

Levi waited too, leaning forward slightly, his head cocked to one side, eyebrows raised. Slowly, he raised one trunk-like arm and cupped his ear with his hand.

'What was that?' he asked. 'I was expecting some gratitude, Taj. Maybe, dare I say it, a touch of jubilation that your plan will come to fruition with our help? But no. I am greeted with... silence. I do so hate our silent world now, don't you? We should rejoice when we get the opportunity. There's that word again. Opportunity. We have, in our grasp, an opportunity.'

'We do, yes,' Taj agreed. 'But I also recall you mentioning two other words. Negotiation and transaction. So, tell me, Levi, for what do you wish to negotiate? What transaction do you want to make?'

Levi straightened up and jabbed a finger at Taj. 'You're a smart man, Taj. I've always thought that about you. You were a banker, right? Of course, you would understand the importance of negotiation and transactions. I knew you would! I knew you, of all people, would understand that it's good business to pay somebody for their services. This world has changed beyond all recognition, but we still don't do nothing for nothing. There has to be a transaction. A payment of sorts. Currency these days is no longer measured in banknotes and coins and that bitcoin shit that I never could get my head around. It's measured in what we have that somebody else might want.'

Levi looked around at his people, smiling benevolently at them all, and they smiled back, knowingly.

'Now, just what do you have, that I might want?' he said, focusing his attention back on Taj. 'What do you think is sufficient compensation for our much-in-demand services?'

Taj stared hard at Levi. 'Just what is it that you want?'

'I love that no-nonsense approach!' Levi grinned, the smile not leaving his face as he added, 'We want seventy-five percent of your food supplies.'

'What?' My mouth dropped open as the cries rose up from the rest of our crew, only to be silenced by Taj who held up his hands to try to calm them. Angry whispering took hold as the tension ramped up, bristling through everyone like an electrical charge set to explode.

Taj turned back to face Levi; his expression grim.

'I always had you down as a smart man too,' he said. 'In which case, you would already know that what you ask is impossible. You honestly think, I would give up three-quarters of what we have? That would be suicide. Even if we win the battle at the harvesting facility, we'll end up starving to death. What kind of victory is that?'

'You exaggerate, my man,' Levi replied, with a shrug. 'You'd be okay. You seem to have done a pretty fine job so far of finding supplies. You girl Evie here was right. You're looking way healthier than we are.'

He nodded to me with a small smile, which I returned with a scowl. I'd always known it would come down to this. Levi was never going to help us without taking whatever he wanted in return.

'The New World has been more generous to you, than to us,' he continued. 'I think it's time you were generous in return and shared what you have, that is, if you want our assistance? Of course, if you don't... well, then good luck to you all.'

'Seventy-five percent though, Levi? That's really your price? You must know that no one would ever agree to such a deal.'

'There are more of us than there are of you,' Levi said. 'You need us, and we need supplies. I think it's a fair trade.'

'Fair, my arse,' growled Jace, and the furious rumblings started again. I saw Levi's crew tense, their mood shifting with ours, their grasp on their weapons tighten. I looked wide-eyed at Taj with a rising panic and he caught my gaze, his lips pressed thin. He felt it too, the atmosphere teetering on a knife's edge, ready to spill over.

'Fifty percent,' he called out, and I heard someone gasp – Iza maybe, who stood not far behind Jace.

Fifty percent. Fuck, that was still a lot.

'Fifty percent is my offer. You can take it or leave it. If you think you can pass up the opportunity to get easy supplies for your hungry people, then fine. We'll hit the facility on our own and you can all stay hungry. Or you can take half of what we have worked damn fucking hard to find and you can all eat and stay alive for a while longer to see our first victory over the Greys.'

The air stilled. A stagnant, awful period of waiting, with everyone still hanging on to the edge.

Levi rolled his broad shoulders back and narrowed his eyes, head tipped back slightly. Triumph danced on his lips as he smiled and instantly, I knew he'd played us. He'd never come here expecting to walk away with seventy-five perecent. Hell, he probably hadn't expected fifty percent. Maybe he was even surprised that they were all still alive after invading our base.

'You have got yourself a deal, Taj. Fifty percent it is. A healthy negotiation, wouldn't you say?' He glanced back at his people, who met his smile with smug grins of their own. 'Of course, I will expect a downpayment as good faith. After all, I need to know that you wouldn't go back on your word.'

'My word is good,' Taj replied, sourly.

'I am quite sure it is, my man,' Levi replied with so much joviality I wanted to whip out my blade and give him a scar on the other side of his face too. 'But I have people to assure. This mission is risky as Hell and they need some guarantee that they will get their just rewards. So, let's say, we take twenty-five perecent now as a downpayment on our services and the rest we will take when the job is done. I think that's only fair.'

Taj hesitated, before motioning to Vik and Lenny. 'Okay, go get them their twenty-five percent.'

'Wait,' Levi called, holding up his hand and gesturing Vik and Lenny to stop. 'You will take my comrades here, Mr. Warren and Mr. Evan with you, so they can assess your supply levels for themselves. I'm not saying that you might see fit to pull the wool over my eyes about how much you have, you understand, but it's important that we are all in agreement about what's fair. We all got to be singing from the same hymn sheet, as my mother would have said.'

Letting two of Levi's men into our base was suicide. It was the end. Taj knew it just as we all did. You couldn't get to the supply room without seeing the kind of set-up we had here, and Levi would leave this place knowing it was a much better base than his damp, dark cellars under St. Paul's.

But we had no choice. If we denied Levi his right to check the supply room, he'd believe we were trying to hide just how much we had and this whole deal would fall apart.

God, how I wished we could turn back. Forget the plans. Forget fighting back. Just keep surviving the best we could. No Levi. No deal. Just us.

Just me and Tom.

I winced inwardly at the reedy voice whispering in my head. At the utter selfishness of it. At the cowardice. At the guilt which rose ugly and twisted inside.

Taj nodded his reluctant agreement, trying to hide in his expression what we clearly all knew, and I watched, with a sinking feeling in my stomach as Jace and Gav helped the two men up onto the platform. Mr. Warren, a tall bald-headed man with a long scar snaking over the side of his skull, and Mr. Evan, who reminded me a little of a younger version of Lenny with his ruddy nose and flushed cheeks, followed Vik and Len through the entrance of the platform, their gaze missing nothing as they went.

Levi watched them go too, his head raised, hands on his hips, wide chest jutted out, looking everything like the victor who'd already won the battle of Central Hall, and not just the victor of fifty percent of supplies, consisting mostly of tinned fish, tinned fruit and powdered milk.

Looking over at Tom, he winked, and grinned wide, his gold tooth glinting. Tom squeezed my hand but I could barely reciprocate.

Despite the heat in the tunnels, a shiver rippled across my shoulderblades and seeped under my skin, bringing a coldness to my bones.

No matter what Taj had said, we did need Levi's crew to help us raid Central Hall. There was no way we could do this on our own. We needed more people to join us to stand any chance of defeating the Greys.

So, why did it feel so much like we'd made a deal with a monster, just to defeat another?