When our group had stumbled into Levi's quadrant, he'd made it clear that no trespassers were allowed without his strict permission.

The Black Zone needed no such statement to be made. There were no guards to tell us not to enter. No signs instructing us to turn back now. It didn't need signs or guards, because no human in their right mind would even consider walking through that sinister, towering wall of thick, dark cloud, not unless they were being forced to by the Greys.

I could only imagine how it must have felt to all those humans – men, women, children – being marched through the ashen barrier of the Black Zone, unable to fathom what horrors awaited them on the other side.

And yet, here we were, voluntarily about to do just that.

I crouched low, nestled into a spot between Tom and Jace, looking across the expanse of St. James's Park where the edge of the Black Zone cut across the park, severing it almost halfway. Without any street lighting, the park was a province of silhouettes and gloom, but it was suprising how the Black Zone seemed to absorb even the darkest of shadows, like a slash of vantablack across the landscape.

Jace whistled low between his teeth. 'Well... shit,' he said, seemingly unable to muster up any other words.

I got it. Being this close made me feel a little breathless. The thought of walking through it – touching it, breathing it in – made my pulse quicken and my stomach tie up in knots.

'What the bloody hell is that thing?' Jace whispered.

'Some atmospheric effect created by their crafts, I guess,' Tom replied, as if he didn't know, which of course, I knew he did.

'And you and Lena walked through that and lived to tell the tale?'

'We lived to tell the tale,' Tom said, nodding, not taking his eyes off the wall.

Maybe they lived because they're both Greys. Maybe you're all about to be marched to your death. Maybe that fucking wall of cloud is going to swallow you all whole and spit out your bones.

I swallowed hard, trying to shake of that cold touch of doubt. 'And you're sure we can't use the tunnels?' I asked.

'I'm sure,' Tom said. 'The tunnels into both Westminster and St James's are blocked. There's no way in underground.'

'Not the kind of adventure you were hoping for, Lara?' Jace said, his tone lightly-mocking, even if his face displayed none of his usual playfulness when he went into joke-mode.

'I'd live through any of Lara Croft's adventures rather than go through that,' I said. 'It's like it's alive. Like one of those two-way mirrors where we can't see in, but someone is on the other side watching us.'

'Terrific,' grumbled Jace. 'I feel so much better after that pep talk. Cheers, Evie.' He glanced over to where Taj and Lena were waiting, together with Levi and Mr. Warren – who we'd discovered was actually called Seb – and nodded in their direction. Taj held up a fist and motioned for us to start moving forwards, which we did, staying close together as we headed towards the next copse of trees for cover, cutting through the long, uncut grass that now grew wildly across the park.

To our right, the surface of the lake glistened slick and oily under what little moonlight there was. It was unearthly quiet here, apart from the intermittent croaking of frogs and the chittering of crickets. I was used to the late-night noise and bustle of St. James's Park – people walking home after a night out on the town, couples taking a walk through on their way home after a romantic meal, the sound of cars and buses around the edge. The silence here felt as wrong as it did throughout the city now. It felt abandoned. A ghost-town, home only to the whistling night's breeze in the treetops and the low hum of insects.

God, I didn't want to walk through it. I didn't want to see what was on the other side. Every instinct was screaming at me to turn around and run, that no good could come from this, and yet, I knew I had to. The people trapped inside Central Hall needed us. They needed to know that hope still existed. That we wouldn't just leave them to whatever fate awaited them at the hands of their abductors, whatever the Hell that might be.

Jace had run to the next tree, joined by Gav and Abby, who had cut in from the left. He held up his hand to motion for us to hold. I glanced behind, seeing a small group of Levi's people at the post we had just held, and others from both crews keeping low, zig-zagging across the park behind us, shadows flitting through the long grass. There was probably about thirty of us in all and although it was more people than we'd usually risk above ground, it just didn't seem enough to tackle whatever awaited us at Central Hall. Tom and Lena, however, had other ideas and believed that with enough explosives and fire power, we could confidently hit the target and make it out again. As luck would have it, one of Levi's crew – a university student called Mali - had worked part-time at the basement café in Central Hall and had backed up Tom and Lena's route through the building, even confirming some strategic exits that we could use that would work better.

And yet, still the unease wouldn't fade.

'Do you remember the bike ride in Brighton?'

I turned to look at Tom, my eyes widening in surprise. 'You're thinking about that now?'

He shrugged. 'It just came to me. Do you remember?'

I did remember. Tom had never been very good on a bike. I'd never seen someone's legs so completely unable to master pedalling as his. It was almost like his legs were a separate entity, powered by some old retired part of his brain that just thought fuck it, I'll let them do whatever they want, I can't be arsed. I hadn't thought about that day since before he'd died. It hurt a little to think about it, but not as much as I thought it would.

'Do you remember what you said to me before we set off?'

I frowned, thinking back. 'Yeah. I told you that we didn't have to go, if you didn't want to. Is this your way of telling me that we don't have to go in there? This was your plan, remember? Vive le révolution and all that.'

Tom studied my face, his heavy gaze sweeping over my features. 'I don't want to do any of this, Eve. I don't want to be a revolutionary. I don't want anyone to risk their lives for all this shit. I don't want to take lives to ensure our survival. I don't want this at all. I just want you and us and a life together.' His fingertips found my lips and he traced the edge of my mouth, his expression troubled. 'But we can't have all that while that still remains.' He gestured to the Black Zone. 'We can't live freely without risking our lives. We can't have what we want without doing everything we can to survive, even if those things are terrible. Even if those things turn our stomach a little. Even if it means killing, before others kill us. I don't want any of this, but I will do whatever it takes to not let you go again, but that doesn't mean you have to be a part of it. Any of it.'

I understood. He wasn't just talking about the raid. He was talking about the plan for Levi. He knew how I felt about it, how I wasn't comfortable to take the lives of those who were helping us now, just to save everything we had worked so hard to earn – our base, our supplies, our survival.

'Are you giving me a get-out-of-jail-free card here?'

Tom blinked, reaching inside for the reference. 'I'm saying to you that I understand how you feel and that I love you for it. I love that you're still you, despite all of this shit. Despite everything that's happened. You're still the Evie I remember. The one who stands her ground and goes against the crowd. I just wish I could be the Tom you remember and the not the one who's prepared to do all these terrible things just to stay with you.'

My mouth opened in shock and I pulled him closer and pressed my cheek against his. 'You are the Tom I remember,' I said, my mouth close to his ear. 'You are. This isn't the same world Tom and I lived in together. Things are different now. He would have adapted, just like we all have. Who's to say he wouldn't have suggested the same?'

I pressed my mouth against his skin and held him there. Over his shoulder, I could see the huge form of Levi hunkering down next to Taj. 'Just please say that we won't do it, unless he leaves us with no choice. Please, Tom.'

He drew back a little and I hated how the dark cloud reflected in his eyes, making them look almost completely black. 'We put it to a vote, Eve. Everyone decided, not just me.'

'I know,' I said. 'But we can persuade them to reconsider. Together, I know we can.'

Tom glanced away, looking into the tumultuous black wall. 'Together,' he murmured, almost to himself. 'You and me. Who'd have thought it?'

'Which is why there's no way I'm turning back now,' I said. 'We're going through that thing and we're going to do what we came here for.'

He chuckled low and soft, but when he looked at me, his gaze was weighted with an intensity I'd come to know as more Grey, than Tom. 'You always were the most determined woman I'd ever met.' He gestured towards Jace with a nod. 'Come on, we're on the move.'

Jace had darted forward again, with Abby and Gav not far behind, and we followed his pathway through the long grass, still keeping as low as we could. It was an uncomfortably warm night and I'd thankfully chosen not to wear a jacket, but my shirt still felt like it was plastered to my skin. The air here should have felt cool and refreshing, particularly after the first part of our journey had been through the stuffy, sweltering tunnels from Charing Cross, but instead it felt just as suffocating, almost as if we weren't outside at all.

We moved closer and closer, and all the while the Black Zone waited, seeming taller and denser the closer we got.

Jace, Abby and Gav were almost upon it now, as were Taj, Levi, Seb and Lena coming up from the left and I held my breath, stopping in my tracks as they soon reached the wall of cloud and, within seconds, all disappeared into its black depths.

'Evie, come on,' Tom urged, glancing behind him.

Swallowing hard, I continued, still scarcely able to believe that there were no Death Squadrons patrolling the park, so arrogant the Greys were in their belief that the survivors would never dare to breach the Black Zone. To be fair, I didn't blame them.

I came to a stop, just a couple of feet behind Tom, who stood holding his SA80 to his chest, just in front of the ominous wall of cloud. Behind us, the dim light of the city with its shadows and ever-pervading gloom had never looked so inviting.

Jace might not have liked my description, but the Black Zone did look alive.

In the Old World, I'd always loved the substance of clouds. Plane journeys that took you up above the clouds, would have you almost believing that you could walk on them, feel their bumpy terra firma under your feet, run your hands over their surface and feel something – not just air which your body could pass through easily.

This cloud looked different. Malevolent. Dark. Alien.

And yes, it was dense, almost like you could cut a slice through it with a blade, but even as I thought that, I imagined cutting though it like it was skin and the whole Black Zone screaming out in agony. Would it feel us as we trespassed its borders? Would it know that we were there, carving our way through its flesh?

I moved alongside Tom. 'Will it know?' I whispered, feeling stupid for voicing my fears, but needing to know. I thought he'd laugh at me, but instead, his smile was warm. Kind. Enveloping.

'It's just a wall. A mask. Something to hide behind. It's what we're good at,' he said. 'But, it's not real. All masks can be destroyed eventually. Every single one.'

'Even this?' I said, looking up as the surface of the cloud moved, rolling upwards in dark waves. It towered so high that I couldn't see the top.

'Even this.' He reached out to touch my hand lightly, drawing my gaze away from the cloud to him. 'You know, standing here, your eyes look completely black.'

'As do yours,' I replied, then smiled wryly. 'You like my eyes black?'

'I like them the way they are.' His fingetips brushed over mine. 'I always have.'

Energised by his words, his touch, I took a deep breath and stepped forward, reaching out with one hand, until my fingertips were just an inch away.

I could do this. I could. I'd lived through Tom's death, the death of everyone I had ever known, and the death of the Old World. I could live through this too. One damn wall of cloud wasn't going to stop me now.

1... 2...

'Evie.'

I stopped, turning to look at him, marvelling at how I'd never thought I'd see his face again, let alone be standing next to him, fighting this war together.

'I love you,' he said. 'You do know that, don't you?'

His brow was crinkled, his eyes suddenly so wide and so open, so honestly raw – so Tom.

'Yes, of course. I've always known.' And I had. You don't get to have been loved by Thomas Morgan without knowing it with every inch of your being. It was a love that no artist could ever have captured.

'No,' he said, his frown deepening. 'No, forget before. Forget what you knew. You know it now, right? You know that I love you?'

I was floored by that then. By the realisation that he did. Not just Tom, but the Grey too. Whoever he was now, whatever he was, he loved me, and it was a love that both thrilled and scared me, because I knew what lay behind the mask and I didn't care. I loved him. Him. I knew I shouldn't, but I did. He wasn't Tom, not really. But he was everything I loved about him and more.

'Yes,' I said, snaking a hand around his neck and pulling his face to mine, kissing him hard. 'I know.'

'Good. Don't forget that. Please,' he said, before smiling almost giddily. 'Okay, let's get this over with.'

We were mad then, I think. Completely and utterly mad, declaring our love for each other right in front of this rolling wall of darkness, right before we stepped into the abyss, the unknown. But I liked this kind of madness. It invigorated me, like every nerve-ending was aflame.

'Yeah, let's do this,' I said and together, we stepped forward, into the Black Zone.