“Guess.”

“Red, seven,” I snap.

Chiu flips the card and we fall silent.

“Lucky guess,” I say.

“This one,” Chiu says, holding up another card.

“Reverse turn, any colour,” I say.

Farah holds up one of her cards.

“Plus-four,” I say. I wince because that card was coming for me.

“What’s going on?” Farah says.

“Blindsight,” Chiu says, with satisfaction. “Like I said, you have a superpower, Kyle.”

“Not much of a superpower,” I say.

Farah grins. “Not unless we take you to Vegas.”

The sky is black and nothing, and we can only see by the grey sheen of unlight. It doesn’t frighten us here though. This place is safe, tethered by the weight of people who hold this place in their mind.

“I think we’re going to be OK,” Chiu muses.

“OK?” Farah sounds dubious. “That sounds like a stretch.”

“Kyle is going to get us to the machine and get us home.” He nods. “With his superpower.”

“No pressure then,” I say.

“I’m going to see my parents again,” Chiu says, his eyes shining in the unlight.

Farah doesn’t respond. I’m worried about her; she picks absently at the makeshift bandage wrapped around her damaged hand. For a moment, I imagine staying here for ever. I can go outside here. I have friends. I have Farah.

But Farah’s dying in the ordinary world and if she’s stuck here, there’s nothing they can do to save her there.

And I have unfinished business in the ordinary world. Things I need to get back to, even if I don’t completely remember what they are right now. There’s Mum and the question of what I was doing in the street that day. Father Michael. Her note on the kitchen table. “Exciting news!” The memory of searching through papers and my panic. I was looking for something: something important enough to make me leave the house for the first time in a year. I have to find out what it was before it’s too late and the longer I spend here the worse my chances get.

“That’s it,” Chiu says, after I drop my last card on to the pile. “I’m going to bed.”

He rolls away from us, curls into a tight ball and falls instantly asleep.

“He’s pretty incredible at that,” I say.

Farah shuffles closer to me and rests her head on my shoulder, looking out over the London skyline. “Can we watch for a little bit? I’m not sleepy yet.”

We sit quietly, the black expanse above the narrow arc of the Earth looks more like the absence of a sky than a sky, but it’s not as terrifying as it used to be. London glows beneath it with a heavy grey-orange light – not the city lights I’ve seen on television, but a liminal sheen, like the pith of the city is bleeding through into this world.

“The one everyone calls Big Ben is really St Stephen’s tower,” I say. “It’s the bell that’s called Big Ben.”

“I knew that,” Farah says.

“Did you know that the real name for the Gherkin is its street name: 30 St Mary Axe?” I add. “And next to it, the Walkie Talkie, that’s 20 Fenchurch Street.” I glance at Farah and see that she’s smiling ruefully. “Rubbish names, right?”

“Please tell me the Shard is really called the Shard, though?” she says.

“Yeah,” I say. “It is.”

“Phew. That’s my favourite.”

I point down towards the murky basin of London. “UCL is down there, I think it’s a straight run from here.”

“What if we get lost again?”

“I don’t think that’s going to happen. I can feel it from here. We’re close.”

She narrows her eyes. “You’re creeping me out with all this zen mystic stuff, you know that, right?”

I laugh. “I’m creeping you out? You can talk, octopus-girl.”

She doesn’t find it as funny as I thought she would. Her smile fades. “I’m sorry,” I say. “I don’t know why I said that.”

“It’s fine,” she says.

“How is it?” I ask, gesturing towards her hand.

She unwinds the makeshift T-shirt bandage and inspects her hand, the spot where I cut off several of her fingers. The wounds have begun to seal over but the hand is still swollen, like it’s been slammed in a car door.

“Fine, I guess.”

“Does it hurt?”

“No … but I can feel it, I know it’s going to come back.” She hesitates. “Thank you for what you said in the shop. About how I had to get back so we could hang out in the ordinary world. It helped.” She wraps her hand slowly, methodically. “You know, it sounded for a minute back there like you were asking me out.”

I feel myself turn red. “Oh … I didn’t mean…”

She darts forward and kisses me on the cheek. It’s gentle, brief, but not exactly sisterly. I freeze and she draws back, looking a little embarrassed. I realize a second too late that maybe that was my moment and I blew it.

Then I remember something. I lean awkwardly to get my hand into my jeans pocket and I find the gold dolphin necklace I found in the hotel. I hold it out in the palm of my hand for her. “I got this for you,” I say. “It’s a present.”

Farah stares at it. “It’s beautiful.” She picks it up so it hangs loose. “It’s the most beautiful thing.”

She turns, lifting her hair so I can put it on her. My fingers tremble as I drape the necklace over her shoulders and join the clasp. The back of my hand grazes the smooth nape of her neck and her skin is so hot it feels like I might scald myself. She turns to face me, smiling, admiring the small, shining dolphin that curls round a drop of pure sunlight.

“I’ve been meaning to give it to you for ages,” I say. “Since the hotel. Dolphins are a symbol of a free spirit, like you. But they’re also a sign of luck and protection. They were the messengers of Poseidon and there are tales of dolphins saving sailors who were lost at sea and taking them back—”