'You are aware your sister's episode was most likely due to substance abuse?'

There was a brief silence, punctuated by the steady beeping from close by. It was the beeping sound that I'd heard first, the insistent noise reaching out to me in the darkness and I'd followed the beeps up to the surface, like I was following a trail of breadcrumbs out of the deepest part of the forest.

I knew what it was. I'd heard it before, after I'd OD'd the first time and Addi had panicked and brought me to the hospital. He'd taken me to A&E and left. Davey's orders. I'd woken up surrounded by strange faces with cold, unsympathetic eyes and that irritating beeping sound which haunted my sleep for days afterwards.

'Yes. She's on a drug counselling program, she's dealing with it. At least trying to anyway. This is just a blip.'

Not Claire. Not my sister. A man's voice. A man's voice that I recognised.

I froze just under the surface, scared to open my eyes.

'Well, Mr. Brogan, I hope for your sister's sake that you're right about that. I'll give you these anyway,' the woman said.

'She has all the leaflets. I told you, she's on a program.'

Another pause. A sigh.

'They're for you, Mr. Brogan. Advice and support services for families affected by addiction and substance abuse. Make sure your sister stays on the program.'

'With all due respect, Nurse, no fucking do-gooder leaflet is going to tell me how to look after my sister. I'm perfectly capable of doing that myself without people preaching at her, or me for that matter.'

I didn't need to open my eyes to know the nurse had taken a step back. I would have backed away from that voice myself if it wasn't for the fact I was pretending to be asleep. I heard her shoes squeak on the floor as she moved.

'Fine,' she said, her own voice cracking nervously. 'One of my colleagues will be along in a short while to check her temperature again.'

The scrape of curtain rings on rails and the whisper of fabric moving told me the conversation was over. Soft footsteps padded away. I waited, muscles tensed.

'You can open your eyes now.'

Fuck.

The mysterious stranger who'd saved me from God-knows-what, stood at the end of the bed, still clutching the leaflets he'd been given.

He was real. I guess I'd always known that he was and that he'd never just been an imaginary creation vomited up by my drug-screwed mind. I remembered too clearly the way his arm had gripped me around the waist, the touch of his hand clasped with mine, the intensity of his stare, the tiny scar on his nose. It would have been easier to accept that the whole thing was nothing but nightmarish make-believe, but I couldn't pretend any longer. He was real, just as all of this was real.

I wanted to believe he was normal, standing there, looking like he could be just another guy, just someone who could have been my brother if I had one. He looked normal, with his Berber-lined denim jacket, charcoal t-shirt and black jeans. He looked normal with his dark hair closely cropped into his neck and worn slightly longer at the front, pushed back from his forehead. He looked normal with the slight tinge of red to his facial hair and the way he arched a dark brow at me as I stared at him. Everything about him screamed normal, but he wasn't. I knew he wasn't, because while I remembered his physical touch and his voice, I also remembered what he had done. Images of him raising his arm, of forcing the air at the other guy, might have seemed like nothing but a bad dream, but it had happened.

I'd seen him.

With a whimper, I pushed myself backwards until I was practically against the wall, pulling my knees up into my chest and bunching up the starched white sheet underneath me, revealing the plastic mattress of the emergency bed. Wires stretched from my torso to the monitor on my right, where the little green blip pulsed across the screen. I gasped as I looked down, realising the thin sheet covering me had slipped and I pulled it up quickly, clutching it to my chest.

'What are you doing here?' I croaked out the whisper.

He threw the leaflets down onto the bed near my feet. 'Well, I'm certainly not here to sit in a circle with other families affected by substance abuse, holding hands and singing Kumba-Fucking-Ya. Get dressed, we have to leave now.'

I gawped at him. 'I'm not going anywhere with you. I don't know who you are.' It came out louder than I'd intended, a rush of panic that hit the volume dial and he winced, moving quickly to the edge of the curtain that was drawn around the bay and glanced out into the unit beyond.

He looked back at me, the irritation clear in his eyes. 'Whether you know me or not, right now, I'm the only one who's going to get you out of this shit heap of danger you've found yourself in, so if you're planning on staying alive for the immediate future, I suggest you get your arse up off that bed and get dressed.'

Despite my fear, his arrogance irked me. Indignant fire sparked something inside, that reckless part of me that couldn't help but kick-back even if it meant digging a deeper hole for myself.

'I'm in a hospital,' I said. 'No offense, but the only danger I appear to be in is from the total stranger who's just masqueraded as my brother and is now trying to get me to leave with him.'

Pulling the curtain back into place, the man edged closer and I instinctively pulled my legs in tighter, getting ready to scramble off the bed. Noticing my reaction, he stopped, but the threat in his eyes lingered nevertheless.

'You think I'm the dangerous one here?' he hissed, scowling. 'Trust me, I've had plenty of opportunity to hurt you, playing the doting brother all alone by your side, waiting for you to wake up. I could have had my hands around your throat and squeezed the bloody life out of you, before anyone would even have noticed they had another dead junkie in here.'

My eyes widened, my breath catching in my throat. How long had I been here with him, by my side, watching me?

He leaned in closer, dropping his voice to a cold whisper. 'Outside in the waiting room is a Transport for London officer who came in with you after your little episode on the Tube. He's waiting for you to wake up so he can charge you with pulling the emergency lever on the train for no justifiable reason and then, a Metropolitan police officer is going to come in here and arrest you for possession of a Class A drug. If that happens, you'll be taken to the closest police station and thrown in a cell, and then I'll have no way of getting to you. Others will though.' He shrugged. 'That's of course, if you even make it there in the first place. My bet is that you won't even make it out of A&E.'

The little pulses on the screen moved faster, the beeps growing in intensity.

'I pulled the emergency lever? I don't remember doing that.' I shook my head, sending small echoes of pain throbbing through my temples and I rubbed a hand over my forehead, my thumb finding the tender spot and massaging it gently.

'Yeah, you pulled it,' he said. 'Right after you started OD-ing on the train and had a screaming fit.'

'What?' My eyes snapped to his. 'But I didn't OD. I didn't. I never took anything.'

'They found the wraps of coke in your bag.'

'Maybe they did, but I didn't bloody take it,' I replied, anger flaring. 'I took some in the morning, sure, and yeah, I was going to take some more but I swear, I didn't. I... I wanted to. I really fucking wanted to and I went to the bathroom to take it, but I didn't. I don't have a clue why, I just didn't.'

'Well, I know you didn't,' he said, rolling his eyes. 'But them lot out there, they just think you're a dirty little addict, don't they?' He gestured beyond the curtain. 'All they know is that you flipped out on the train and pulled the lever, and there's a whole carriage full of people who're going to confirm that.'

I stared at him, the unease growing. 'How do you know I didn't take the drugs?'

Moving closer, he leant down, resting his hands on the edge of the bed.

'Because I know what you saw on the train, Casey.'

'You see too much,' the man had said. 'You shouldn't see.'

I swallowed and my throat resisted, pain burning there. 'Are you one of them?' I whispered. 'Are you like the guy on the train?'

He smiled then, a ghost of a smile that haunted his face. 'No,' he said, softly. 'No, I'm not like the guy on the train.'

Holding my gaze for a second, the smile faded as quickly as it appeared and he pulled back abruptly.

'If I was one of them, I would have killed you by now,' he said, matter-of-factly. 'I would have killed you the other day behind that club where you do your deals. In fact, if I was one of them, I would have killed you on New Year's Eve. And I know you have no reason to believe me, but if you stay here now, you probably won't leave this hospital alive. They might as well bag and tag you and ship you straight down to the morgue.'

'Wow,' I breathed. 'Does promising certain death usually have the desired effect?'

'Depends on what effect I'm aiming for,' he said.

'And what effect are you aiming for? Scaring me shitless?'

'Whatever the Hell gets you up off that bed, to be honest. Now, are you going to come with me, or not?'

I chewed my lip as I stared at him. He was right. He'd had enough opportunities to kill me if he wanted to and I had no idea why on earth he was helping me, but the only way I was going to find out was if I went with him.

'Okay,' I said, wondering if I had actually gone mad. 'Fine, I'll go with you. On one condition.'

He whistled out a breath, which turned quickly into a choked laugh. 'Let me get this straight. I'm trying to save your arse and you want to do a deal with me?'

'No. No deals.' I shook my head. 'I just want you to promise to tell me everything.'

'Everything?'

'Y-yes,' I said. 'I want to know what they are. I want to know why they want me.' I hesitated. 'And I want to know what you are.'

His eyes narrowed, slivers of blue cloaked in shadow that sent a shiver cascading down my back and suddenly I wasn't so sure I wanted to know. I wasn't sure I was going to like whatever he told me.

'Okay, Casey. You've got yourself a deal.' He smiled again and began to take off his jacket, throwing it onto the end of the bed, before tugging on the hem of his t-shirt and lifting it over his head.

'Wait,' I said, alarmed at the sight of his naked, toned chest. Numerous scars marked his skin, some large, some small, all telling a story I wasn't sure I ever wanted to hear. 'What the Hell are you doing?'

'They cut yours off when you were thrashing about and they needed to hook you up,' he said, throwing it at me. 'Put it on.' Grabbing his coat, he put it back on and began to fasten the buttons, while I sat there, holding his t-shirt. It felt warm in my hands.

'Staring at it won't magically make it appear on your body. You have to actually put it on yourself.'

I flinched, looking up to see his gaze fixed steadily at me and I was sure I could see a small glimmer of amusement in his eyes, but it disappeared as quickly as his smile had, the urgency rushing back into his expression.

Flushing, I tugged at the wires, trying to struggle with the sheet as each pad ripped free. He had the decency to turn away slightly as I pulled the t-shirt over my head, the sheet dropping away as I did so, and I thanked what few lucky stars I must have had left that I was still wearing my jeans. I found my jacket and my battered Cons on a chair next to the bed and quickly put them on, as the man moved back over to the edge of the curtain and peered out. Motioning for me to join him, I did hesitantly, hardly daring to believe that I really was going to leave with, and put my trust in, a total stranger, particularly one who had danger written all over him in a pattern of scars.

'As soon as we leave here, you stay by my side and you keep your head down,' he instructed, keeping his voice low, but his eyes still scanning the aisle outside the bay. 'You don't talk to anyone and if I tell you to run, you run. Stick with me and you might – just might – have a chance of making it out of here alive.'

If I'd still been hooked up to the machine, I knew the beeping would have been going into overdrive then. I could feel the furious pounding inside my chest, hard and unrelenting, but I found myself nodding numbly in agreement.

'Good,' he said, sounding almost surprised by my willingness to do what he said. Grabbing my hand, he pulled back the curtain.

Most of the other bays were occupied, curtains drawn to protect the privacy of the occupants within. Voices floated out from behind green walls of fabric. A child was crying, choking on sobs of pain while someone, a woman with a soft but clearly terrified voice, tried to offer words of comfort. A nurse was attempting to convince what sounded like an older man to stay in his bed, but he was kicking up a stubborn storm, his protests getting louder and louder. Another man was howling in agony and demanding that the Doctor 'fix this fucking arm' and the Doctor, in a voice which sounded full of exhaustion, was patiently requesting that the person refrain from using such language.

I grasped the man's hand tighter with each step, barely realising I was squeezing so hard until he squeezed back, not hard enough to hurt but enough to make me register what I was doing and relax my grip a little. We walked the aisle, weaving in and out of nursing staff who rushed here and there, all so busy that they took no notice of us as we walked through the A&E department towards the end of the corridor, where the sign above the double swing doors read Orthopaedic & Fracture, Cardiology & Respiratory and General Out-Patients. He was leading us into the main part of the hospital, away from the TFL officer sat waiting in the A&E reception for the junkie who'd flipped the lever for fun.

The corridor beyond the doors widened out, the human traffic not as frantic as in the A&E department behind us. Our footsteps echoed on the polished floor, our pace not slowing until the man abruptly came to a halt in the middle of the passageway, stopping to look up at the strip-light above our heads which was buzzing furiously.

'What?' I said, puzzled by his sudden attention to the cracked tube. 'What is it?'

The bulb inside flickered, stopped, then flickered again.

'It's broken.' I shrugged at him, wondering why the Hell he would be in such a rush to get away one minute, only to stop and study a broken bloody light the next.

'No,' he said, turning his head to look along the corridor ceiling. 'No, it's not. It's perfectly fine...' His voice trailed off as the other lights in the passage began to flicker. 'It's too late. They're here.'

With his eyes still fixed on the flickering lights, he took a few cautious steps backwards, pulling me with him. 'We're going to have to run, Casey.'

'Wait, why? What's happening? Who's here?'

'I said run, for fuck's sake. Come on!'

Grasping my hand, he broke into a sprint and I followed his steps, not knowing why we were running, only understanding that whatever the flickering lights meant, from the look on his face, it can't have been anything good. As we pushed at the doors at the end of the corridor, a volley of small explosions behind us forced me to look back. Sparks showered the passage, as each strip-light popped violently in turn. Deadly shards of glass rained down in slow motion, almost as if they were fighting their way through colourless treacle and not the air, which seemed to have thickened, ripples spreading out along the corridor towards us.

Something was coming.

The man yanked hard on my arm as we ran into the next corridor, concentrating my attention on the path ahead and not whatever horror lay behind. A screeching noise filled my ears, and a thrum like a thousand wings beating at the thickened air engulfed me, until I felt my head might burst from the pressure. My legs, having somehow found the energy to carry me this far, most likely driven by nothing but a deep, untameable fear, were now starting to relinquish the fight, screaming at me to stop, to give up, to just let them rest. But I knew I couldn't.

We ran past department after department, past people who barely registered our presence and who seemed unfussed by the nightmare that chased at our heels, until finally, an exit sign lit up the end of the next corridor, a halo of light that made me want to cry out with joy.

Bursting out into what looked like the last light of the day, that beautiful final golden glow where indigo hues danced at the edges of the sky, we cornered the building, bulldozing across the white-lined asphalt of a visitors car park.

'There,' the man said, pointing at a black Audi, sandwiched between a beat-up old Astra and shiny newly-plated Mini. 'Quick!' Reaching into his jacket pocket and retrieving his keys, he clicked the fob as we reached the car, the locks opening with a snap, the lights flashing their greeting.

Once inside the car, he switched on the ignition and pulled away in a screech of tyres, before I even managed to hook in my seatbelt.

'Hold on,' he said through gritted teeth, glancing in the rear-view mirror, as we sped through the car park towards the exit.

'What now?' I twisted to look out the back window and cried out, watching as the air ballooned towards like an unstoppable tsunami, growing in energy as it barrelled through the parked cars, flipping some of them onto their sides as if they were nothing but toys. 'Oh my God,' I screamed. 'It's coming, it's going to hit us!'

'Fucking hold on tight then,' he said, turning the wheel just as the ball of energy caught the bumper, spinning us a quarter circle. I tried not to think about how easily it had flipped those other cars, how they'd flown up into the air as if tossed aside by a giant's fist, metal crumpling with ease and windows shattering. The force of the blow sent the back of the car veering to the left, but somehow the man managed to turn the wheels to bring it back under the control, putting his foot down on the pedal as it straightened up.

I closed my eyes tight shut and wrapped my arms over my head as the crash barrier loomed ahead, about to close again as the motorbike in front exited the car park. One final scream of accelerator, one almighty roar of engine and we were clear, exploding out onto the road and I opened my eyes in time to see us narrowly miss a bus which had decided to pull away from the kerb at the worst possible moment. I shrieked as the driver slammed the brakes, but we didn't stop. Instead, the man next to me just accelerated, his eyes constantly darting to the rear-view mirror no matter how far away we got from the hospital. After a while, I knew that whatever had been pursuing us was gone, but my fear was very much still present.

'Where are we going?' I asked, finally managing to find my voice, as I gripped the seat. My knuckles were hurting, the bones begging for some peace.

'Somewhere no one will be watching us,' he replied.

I wasn't sure what he meant by that and I definitely wasn't sure whether I liked the idea of being somewhere alone with him, but any place seemed better than where we had been.

Eventually, he turned the car into a side street. Up ahead I could see the skeletal remains of an old warehouse, blackened, rain-damaged brick somehow working a miracle on keeping the building upright. The high windows were boarded up with rotten sheets of plywood and the roof clung desperately onto the walls, as if frightened to let go. At the front, the shutter was gone, the darkened entrance now a wide-open mouth ready to gobble up anyone or anything that dared to enter.

Reversing slowly into the old building, he braked to a stop where the light seeped through the fractured roof, casting a pinkish-hazy glow onto the bonnet of the car.

Neither of us spoke for a moment, but I sensed the slow release of his muscles as he relaxed back into his seat, even though his hands still flexed tightly around the steering wheel.

I exhaled, not feeling the same release at all, my body still hard and unyielding, maintaining the barrier against everything I had witnessed. I had to keep it up. I couldn't let go, not yet, because if I let go, I knew I'd crumble into pieces and probably never find my way back to be whole again.

'So,' I said. 'I think this is when you explain to me what the fuck is going on?'

He grinned then, a grin that looked more like a pained grimace than a smile. 'Oh, I'll try. But I need to warn you, it's going to take a lot for you to believe me.'

'Then why don't you start with something I will believe?'

His forehead crinkled in question. 'And what's that?'

'You can start by telling me your name.'

He let go of the wheel, his hands dropping into his lap.

'Ethan Drake,' he said. 'My name is Ethan Drake.'

It was a name. Just a name. The most simple, most believable thing he could have said.

Yet as soon as the words left his lips, I knew it was a lie.