I hold my breath and hope I look calm even though my insides are doing somersaults. Then I watch Amy, trying to figure out if she knows what she saw or thinks it’s her eyes playing tricks. She’s barely said a word since they arrived, and I don’t know if that’s because of me or her parents.

“Dessert is served!” Jay shouts up the stairs, and I breathe out too loudly.

“Come on. Mum’s desserts are awesome.”

On the way down, I reply to Zak.

What is it?

And he messages back instantly.

I’m not sure. Just come.

That wasn’t part of the plan. I can’t leave the meal without attracting attention…unless they don’t know I’m gone.

“I’m just going to the toilet,” I say, but, while everyone is distracted, I gently open the front door and leave. I run to the end of the street, then dial Zak’s number.

“I’m outside,” I whisper. “Where are you?”

I hear stones crunching from the other side of the wall, then a grunt just before Zak’s head appears a few meters away.

“Come over,” he says. “You’ll want to see this.”

When I don’t move, he says, “This was your idea. Come on.” But this wasn’t my idea. I should be having awkward conversations with the Pearces; we shouldn’t both be trespassing. How am I going to explain this if we’re caught?

“Tom,” Zak hisses. “Quickly.”

He’s pushed the brown garden waste bin against the wall so it’s easy to climb over.

“How’s it going?” he asks. “Did you save me some leftovers?”

“This isn’t funny.”

“I’m not laughing. I’m just hungry.”

Zak smiles, but I don’t have time to muck about. He’s making light of this because it’s his way of coping. If he didn’t joke, he’d convince himself the police were on their way.

“What did you find?”

He starts walking away from the house, deeper into a garden that feels infinite in the dark. Amy’s house is lit up through the patio doors, and I’m tempted to try them. Another look in Will’s room could give me the evidence I’m searching for. But, whatever Zak has found, it’s in the opposite direction.

“Where are you going?” I whisper.

“You’ll see,” he says, his voice far enough away to make me nervous.

I know I said I wasn’t scared of the dark, but that changes when you don’t know what you’re walking into.

He stops quicker than I expected, his phone’s flashlight piercing the gloom. He’s pointing it at a tree.