“I know.” Guilt hoarsened my voice. “I’ve been ill.”

“Yeah, like always. Her mum’s been a bitch. Have you even called her?”

“I… Not yet.” I looked at the Mark on my hand again. It was all I could think about. Hannah hadn’t even crossed my mind.

“But suddenly you’re worried about Justin,” Pete sneered. “Hannah deserves better.”

“I know.” I closed my eyes.

“And I’ve been telling her so.”

“You’ve no right.” My eyes snapped open.

“I’ve every right. I have no idea what’s going on with you, but then I never did. Neither does she.”

“I’ll be back at school soon and back to normal.”

“This is normal for you.”

“Pete…” My eyes were caught by my own hand. As if it were under a spotlight that suddenly dimmed, the stain darkened right in front of me. I almost gagged. “I was calling to find out about Justin, I’ll sort things out with Hannah, but–” I remembered what Dad had said when he asked if I felt guilty. “I fought with him just before he went missing, I feel really bad. I just want to know that he’s alright. That it isn’t my fault.” The lie felt like ashes in my mouth, but it was enough to give Pete pause.

“If you’re trying to pull something–” he said finally.

“I honestly want to find Justin.” Every atom of my body trembled with sincerity. He’d hear it. He knew me.

Eventually he sighed. “Fine, whatever. We went to the Empire quite a bit and we hung out at the Walkabout a few times, but I can’t see him in there without Harley. He and Tamsin loved Camden and…” He paused. “I guess it doesn’t matter if I tell you. He spent a lot of time at the Science Museum.”

“The Science Museum.” Something about that made me sit up.

“Yeah. Don’t laugh.”

“I’m not. I might check out the Museum then.”

“Fine.” Pete didn’t hang up. The sound of his breathing reminded me of all the time I’d spent on the phone with him over the years. I was tempted to ask what he thought of last night’s telly or what I'd missed at school. The words quivered on my lips, but never surfaced.

Then the dial tone hummed in my ear.

And in my mind the fourth entry of Oh-Fa’s journal:

Less than an hour later the hole is wide enough to admit two men and of the original icon, only the feet remain.

Now stairs descend from the sand but, despite the blazing sunlight, I can see no further than five treads; the sixth is covered in darkness as impenetrable as treacle.

I have returned to the tent to collect my tools and admit that I am reluctant to go back to the crypt. Pimples speckle my arms in defiance of the heat. It seems strange that we have been camped above the dark-tombed dead this whole week.

I cannot shift the words of the I-Ching from my head, they circle like hawks: The way that can be described is not the true way.

Something about this feels wrong and I would give a lot not to have to descend that staircase.

I think of my son, perhaps newborn. Not that. Never that.

It is time to go.

Instead of going to school I stood on Exhibition Road, leaned against the railings that hemmed the street and looked up at the flag above the building. It snapped in the wind but I couldn’t hear it over the road noise. My eyes followed the lines of columns that bordered the windows, down the smog-stained stonework, to the worn gold name above the huge doors.

I hadn’t been to the Science Museum since I was a kid. The website had said there were five floors and I had no idea which of them Justin might have headed for.

I shaded my eyes and peered at the windows, secretly hoping for some sort of sign. But there was nothing to see but sun glinting from darkened glass.

A stream of people poured from South Ken station and knocked my elbow as I glared at the printed map scrunched in my gloved hand.

Irritation forced speed into my pulse. There were too many people here, too many ways for the dead to disguise themselves. I had to get off the street. I shoved the map into my backpack and dodged through a gap in the crowd to run up the museum steps.

Then I paused. The shadows around the great doors seemed too dark, too cold. I licked my lips and strained my ears. The street sounds continued, noisy and normal. Shaking my head I ran in, towards the well-lit security checkpoint.

Time was getting tighter. Justin had to be here.

I queued behind a school group then handed my backpack to a guard whose smile was already looking strained.

“Got any sharp objects?” He raised his eyebrows at me.

“No.”

“Any of this?” He gestured to a laminated sheet showing a range of lethal weaponry.

“No.”

“Alright then.” He briefly lifted my cardigan from the top of my pack so he could see my purse, Oyster card, keys and can of drink. Then he handed my pack back to me. “Enjoy your visit.”

I stood by the information desk in the gaping entranceway. There were too many options. I was planted like a rock in a sandstorm, my feet unsure which way to turn. Should I take the lift? Start at the Garden and work my way up to the fifth floor? Maybe I ought to head straight on, past the ticket booth for the iMax? According to the map, that route would take me through an area dedicated to space travel and into a display about energy.

Above the ticket booth there hung a huge metal hoop. It was so big it reached the third floor. An electronic display inside its rim drew my eye. The little lights danced endlessly, trapped inside the circle, seeking a way out that they would never find. It spoke to me. I headed towards the glowing ring.

Beyond the light-filled ring I caught my breath. Ahead of me a space shuttle hung in a dark-shrouded room. People walked towards me in pairs but I ignored their irritated huffs, refusing to move and forcing them to part in order to pass me. It was dark in there, full of shadow. I took a step backwards; I didn’t have to go this way. There was no guarantee that Justin was on the other side.

But then his voice came back to me: “I was going to study engineering.”

If he was here, he would be in the Engineering section and that was on the other side of the cloying darkness. I straightened my shoulders and walked into the false night-time.

To get out in record time I planned to march through the exhibit, looking neither left, nor right, but then glimmering displays caught my eye. There were whirling representations of planets and stars, and engines from real shuttles. They looked like Dalek mutations but had propelled man into the vacuum of space and brought him safely home.

Awe filled me and instead of striding straight on, I faltered and my eyes flickered from plastic astronauts to their replica equipment. Then I saw a quote on the wall.

“An unseen force pressed me to the couch as if lead had been poured over me. Breathing became more difficult. The weight bearing down on us robbed us of the ability to speak. It ate all sound, leaving only wheezes and grunts.”

I stood reading and rereading it. “It ate all sound”. In my mind there was no doubt; astronaut Vasili Lazarev had experienced the Darkness.

Panting like a long distance runner I darted from the space exhibit and burst gratefully into the light of the Energy section.

I bent over until my breathing felt more normal then I straightened. A giant silver plane was suspended just ahead of me as if flying through the giant hall. My shoulders twitched before I managed to suppress the instinct to duck. Embarrassed, I pushed my hair back over my shoulders. The hall was bright, light, silver and white. The only dark patches were on the aged metal of machines from earlier centuries.