Hazell gave Harry a large whisky. He tried to shake the image from his head of Chuck standing in front of that Tube train. It was impossible to forget what he’d seen, but he used the booze to calm his nerves and focus on what these three women were about to tell him.
Then he’d use time travel to save his friend’s life.
I don’t care what they keep telling me about time can’t be changed – I know they’re lying about that. I’ll find a way to save Chuck and Amy.
And Lily.
‘Sally and I were eighteen when we met at university, and Rose was nineteen. We became firm friends quickly, all of us studying to be physicists, but with an obsession with quantum mechanics.’
Harry sipped at his drink. ‘Quantum mechanics?’
Cohen continued the explanation. ‘It’s the branch of physics relating to the very small. It results in what may appear to be some strange conclusions about the physical world. At the scale of atoms and electrons, many of the equations of classical mechanics, which describe how things move at everyday sizes and speeds, cease to be useful. For example, in classical mechanics, objects exist in a specific place at a specific time. However, in quantum mechanics, objects instead exist in a haze of probability; they have a certain chance of being at point A, another chance of being at point B and so on.’
Adler waved a hand in the air. ‘You’re boring him, Sally. Just tell him how it relates to theories of time travel.’
Cohen scowled through her freckles. ‘For most of this century, studies on time travel were based upon classical general relativity. Coming up with a quantum version of time travel required physicists to figure out the time evolution equations for density states in the presence of closed time like curves.’
Hazell laughed. ‘Yes, Sal, that’s so much better.’
Harry took more of the whisky. ‘Can’t you give me the idiot’s version?’
Hazell refilled his glass. ‘Black holes, wormholes, loop quantum gravity, causal set theory, semi-classical quantum gravity, and string theory. In time – no pun intended – all had their champions regarding the possibility of time travel. The three of us decided it was our life goal to make it work.’
‘And you found that one of them did,’ Harry said.
‘Quite the opposite,’ Hazell said. ‘None of them worked and they never will. In 2040, we knew that time travel was possible in theory, but impossible in practice.’
He put the glass down. ‘Are you messing with me again?’
They acted simultaneously, reaching into their pockets and removing a pill.
‘No, Harry,’ Cohen said. ‘Time travel is not only possible; it’s real, and you’re one of the few people to have done it. And it’s all to do with what’s inside these pills, the chemicals in your brain and chronoception.’
He shook his head. ‘And this is the idiots’ guide?’
Cohen continued. ‘The study of time perception or chronoception is a field within psychology, cognitive linguistics and neuroscience that refers to the subjective experience, or sense, of time, which is measured by someone’s perception of the duration of the indefinite and unfolding of events. The perceived time interval between two successive events is referred to as perceived duration. Though directly experiencing or understanding another person’s perception of time is not possible, such a perception can be objectively studied and inferred through several scientific experiments. In addition, some temporal illusions help to expose the underlying neural mechanisms of time perception.’ She moved closer to him. ‘Imagine what it would be like if you could manipulate your sense of time perception to reach back into periods you’ve already experienced; not as memories, but as a physical experience.’
Harry rattled the ice around in the glass. ‘Okay, I think I understand that, but surely if I could do that, I’d only be able to travel to stages in my own life. How could I go to Pompeii or stand on the Titanic?’
Even though I did both.
Cohen’s smile accentuated those freckles again.
‘Have you heard of epigenetics?’ Harry shook his head. ‘What about genetic memory?’
‘Maybe,’ he said. ‘I think I saw a movie once about memories passed down through the generations where some kid was the chosen one to save the world from invading aliens.’
Cohen laughed. ‘Epigenetics is based on the concept of changes in gene expression and of active and inactive genes. Epigenetic scientists study how cells change to adapt to skin cells, liver cells, or even cancerous cells. They also study how genes are inherited and the changes to those genetics that we exhibit, even when those changes are not essential to our DNA. Our experiences, age, environment, and health can affect these changes. For example, studies by scientists and researchers have discovered we receive loads of genetic memories from our parents, grandparents, and further ancestors in an instinctive effort by their DNA to better prepare us for difficult experiences they faced, such as fear, disease, or trauma.’
‘So,’ Harry said, ‘you’re saying I could travel to Pompeii because the location has been passed down through DNA and still lingers in my mind somewhere?’
‘That’s the theory,’ Cohen said.
He tasted the booze warming the back of his throat. Then he looked at all of them.
The Crucial Three.
‘But you cracked that theory.’ He stepped towards Cohen and took the pill from her hand. ‘And you put it all into one of these.’
It sounded incredible, but he knew it was true because he’d experienced it.
‘No,’ Hazell said. ‘We didn’t do any of it.’ Harry saw the shame in her eyes. ‘The three of us are frauds. We didn’t discover the secret of time travel.’
‘What?’ he said. ‘So who did?’
Cohen took the pill from his hand. ‘Ten years ago, a stranger turned up in our office and offered us the missing link to time travel. That link is the combination of the right chemicals connected to the correct parts of the brain. Therefore we use the pills or an injection through a syringe to travel.’
Harry rubbed at his temple. ‘How did I get on the Titanic or into that warzone?’
‘That was my doing,’ Hazell said. ‘The pill Ellie slipped you in Pompeii had the time and location programmed into the DNA. It was the same with the injections I gave you.’
Harry’s brain felt as if it was inside a microwave turned up to full.
‘Who was the stranger who gave you this secret?’
Cohen smiled at him. ‘Can’t you guess?’
He could. ‘It was Amy Croft.’
All three women nodded together.
‘It was Amy who supplied us with the pills and the chemicals to manipulate the brain,’ Cohen said. ‘And to manipulate time and space.’
Harry took a deep breath and moved to the window, his mind throbbing with what he’d heard. He gazed upon those moving around outside. London had a heart, a rhythm and a beat. It was a city of wide streets, hidden places, and joy and desperation in equal measure. There were places to sit and eat, to relax as people went about their day. Vast tall buildings were everywhere, unlike during his youth when they were the exception. Thousands of homes took up less ground space than a shopping centre. The rest was parks and wild spaces, a chance to walk among nature or enjoy the trails on bicycles or horseback while inside the urban jungle. He thought about his life in the city, of growing up there before needing to escape into the army. That hadn’t lasted long and he’d returned to the place he’d missed. He’d seen so much of the world, but London was where he’d always wanted to get back to – inhaling the city’s history because that’s where his sister had taken him on their walks through the capital.
Lily had loved the city and the river, so Harry had assumed his love for those things had come from her. That’s why he was always desperate to return to London, but over time, he’d realised it was something different that drew him back to that place.
If Lily were alive, she’d be here.
There was little chance he could ever bump into her anywhere else in the world. Even now, as he looked out of the window, he imagined she was down there somewhere, waiting for him.
And now he could find her just by swallowing one of those pills.
But he couldn’t get it wrong.
The tests were to prepare him for the Croft murder investigation. Still, at the back of his mind, Harry had known he was using his experiences with the Time Authority for something else: to go back in time and discover what had happened to his sister.
As long as he could get close enough to that day.
That conundrum, if what the Crucial Three had told him was true about some time points being off-limits, was enough reason to try it with Croft first before visiting Lily.
And now he had Chuck’s murder to investigate as well.
He gazed across the capital, standing there as one of the few people who knew the world’s greatest secret.
But he still didn’t know enough as he observed Hazell cradling her drink.
‘What happened when we arrived at the corridor of bright lights with all the doors?’
She smiled at him. ‘All that glitters is not gold, Harry.’
Irritation grew at the back of his neck. ‘What’s that supposed to mean.’
‘What Mary means’, Cohen said, ‘is that you have to be careful with what we call the Doors of Perception.’ She held a pill out to him. ‘As far as we can tell, when the chemicals Amy supplied us mix with the correct sectors of the brain, our minds take us to an infinity of doorways through time and space, and we choose one to travel where we want to.’ She glanced at Hazell. ‘But like any mode of travel, there are always risks involved.’
Harry rubbed his fingers together. ‘I touched one of those doors and it burnt my skin.’
Cohen nodded. ‘That was your mind warning you it was the wrong door.’
The memory was scorched into his brain. ‘If I’d forced my way inside, what would have happened?’
Cohen shrugged. ‘We don’t know, but you wouldn’t have come back.’
Harry examined their faces, convinced they still weren’t telling him everything.
‘What are you keeping from me?’
Cohen sighed and he saw the guilt consuming her. Guilt that wasn’t apparent on Hazell or Adler.
‘What we said earlier about the physical and emotional ramifications of time travel on the human body was true, but we didn’t realise it until we were into the first two years of our experiments.’
The significance of what she meant stabbed at his heart.
‘There have been other time travellers?’
Hazell spoke without a flicker of emotion. ‘There were six we lost. We’ve always assumed they went through the wrong entrance at the Doors of Perception.’
His legs ached as he sat down. ‘Who were they?’
‘Volunteers,’ Adler said. ‘After our TV appearances, we were inundated with them, people desperate to do anything to travel to the past.’ She looked at Hazell. ‘It was a relative of one of the disappeared who tried to kill Mary.’
‘You never searched for them, these missing volunteers?’ Harry said.
Hazell laughed. ‘You want us to search through all of time and space for them? You must be mad.’
He resisted the urge to throttle her. ‘Was it worth causing so much pain and suffering just to be observers of history?’
Cohen sat next to him and touched his arm. The warmth in her eyes cooled his anger.
‘What’s the one thing you want most in the world, Harry?’
He smirked at her. ‘To get out of here.’
She returned his smile and he hoped when he travelled through time again – as he knew he would – it would be with her.
‘Be honest now. Before you came here and met us, if somebody had said you could go back in time only once and only to observe, what would you have chosen?’
He’d tried denying it to himself from the minute he’d first entered the building, but he knew it was futile to keep it from them.
‘I’d see what happened to my sister.’
Cohen squeezed his hand. ‘And you’ll get the chance to do that once we know what happened to Amy, but what if every person on the planet was given that same opportunity to travel in time to see someone again? How do you think the world would receive that?’
Harry thought about it for ten seconds. ‘To go back and see a loved one you’d lost? I guess it would be painful for some, but most would jump at the chance.’
She beamed at him. ‘And that’s what this is all about. Time can’t be changed; the universe won’t allow it.’ She glanced at the others. ‘We know because we’ve tried. So we came up with another purpose for time travel: to allow the world to see those they’d lost for one last time.’ Cohen’s smile lit up the room. ‘Imagine if you could visit your parents when they were younger to see the things they did, or your grandparents or other ancestors?’
‘It would be the greatest thing of all time.’
Cohen let go of his hand. ‘So, do you see, Harry, what this is all ultimately about?’
He did. ‘You don’t have enough of the pills, do you?’
‘No,’ Cohen said. ‘Only Amy knows the chemical composition of time travel.’
He gazed at her. ‘Don’t you mean she knew?’
Cohen stood. ‘Harry, I’d like you to meet your partner for the investigation into the murder of Amy Croft.’
The door opened and he turned to see the person who strode through it.
Amy Croft.