I look out of the window, as the car jolts over the rutted flints, towards the receding shape of her and Shadow, their six feet eating up the miles of marsh, moving fearlessly between the ever-changing ditches and sloughs, and I think, be safe, Kate. Please, be safe.

RICK’S TAXI HAS reached the tarmac road, and is indicating left to go to the station, when Thea looks up from her handbag.

‘I need to get money out. Is there an ATM at the station?’

Rick turns off the indicator, and I sigh. I left the money I drew out yesterday tucked inside a mug on the dresser, where Kate will find it after I’ve gone. Payment for the dinner tickets, which she refused to let us refund, but which my conscience wouldn’t let me ignore. I kept only twenty pounds – just enough to pay Rick, and a bit to spare.

‘You know there’s not,’ I say. ‘Since when was there a bank machine at the station? We’ll have to go via the post office. Why do you need money, anyway? I can pay for the cab.’

‘I just want some cash for the journey,’ Thea says. ‘Post office please, Rick.’

Rick indicates right, and I cross my arms, suppressing a sigh.

‘We’ve got plenty of time until the train.’ Thea closes her bag, and shoots a sideways look at me. ‘No need to be mardy.’

‘I’m not mardy,’ I say crossly, but I am, and as Rick begins to turn across the bridge towards Salten, I realise why. I don’t want to go back there. Not at all.

‘Going already?’

The voice comes from behind us, making me jump. Thea is bent over the cash machine, typing in her pin, so it falls to me to turn and answer the person behind us in the post office.

It is Mary Wren, come out quite silently from whatever back room she was in when we entered the empty shop.

‘Mary!’ I put my hand to my chest. ‘Gosh, you gave me a shock. Yes. We’re heading back to London today. We – we only came for the dinner, you know, at the school.’

‘So you said …’ she says slowly. She looks me up and down, and for a moment, I have the disquieting impression that she doesn’t believe a word of what I’ve said, that she sees through all of us – through all the lies and deception, and knows exactly what secrets we’ve been hiding. She was one of Ambrose’s closest friends and it occurs to me to wonder, for the first time, what he told her, all those years ago.

I think of what Kate said, the rumours in the village, and I wonder what part Mary played in all this. I have never been in the Salten Arms when she was not seated by the bar, her loud deep laugh ringing out across the drinkers. She knows everything that goes on in Salten. She could have quashed those rumours if she wanted to – defended Kate – told the drinkers to wash their mouths out or get out. But she didn’t. Not even to protect the daughter of a man she once called a friend.

Why not? Is it because part of her thinks Kate is guilty too?

‘Funny time to come down,’ Mary Wren says. She nods her head towards the stack of weekly papers, still blazoned with the photograph.

‘Funny?’ I say, my voice cracking a little with nerves. ‘How do you mean?’

‘Awkward time for the dinner to fall, I mean,’ she says. Her face is unreadable, impassive. ‘With the rumours and all. Must have been hard for Kate, seeing all those people, wondering …’

I swallow. I’m not sure what to say.

‘Wondering?’

‘Well, it’s natural isn’t it? To … speculate. And it never made sense to me.’

‘What didn’t make sense?’ Thea says. She turns round, shoving the wallet back in her jeans pocket. ‘What are you trying to say?’ Her face is belligerent, and I want to tell her to calm down, this is not the way to handle Mary Wren. She needs deference, a show of respect.

‘The notion that Ambrose just … disappeared,’ Mary says. She looks at Thea, at her skintight jeans, and her bare breasts just showing through the sheer vest. ‘Whatever his faults, he loved that girl. He would have walked through hellfire for her. It never made sense that he would just … go, like that, leave her to face all this alone.’

‘Well, we’ve no proof of anything else.’ Thea says. She is as tall as Mary, and she stands, her hands on her hips in an unconscious echo of Mary’s stance, almost as if they are squaring up. ‘And in the absence of any proof, I don’t think speculation is very healthy, do you?’

Mary’s lip curls, and for a minute I can’t read her expression. Is it a kind of suppressed anger? Disgust?

‘Well,’ she says at last. ‘I suppose we won’t need to speculate much longer, will we?’

‘What do you mean?’ I say. My heart is thumping in my chest. I look over my shoulder at the taxi, where Freya is playing peacefully in the borrowed car seat that Rick provided, sucking at her fingers. ‘What do you mean, not much longer?’

‘I probably shouldn’t be telling you this, but Mark, he tells me a body’s been recovered by the police and, well …’ She makes a little beckoning motion with her finger and in spite of myself, I find I’m leaning in, her breath hot on my cheek as she whispers. ‘Let’s just say, if it’s proof you want, I think that body might have a name very soon.’

I CANNOT LOSE Freya. I cannot lose Freya.

These are the words that circle inside my head like a mantra as the train speeds north, back to London.

I cannot lose Freya.

It beats time with the rattle of the wheels on the track.

I cannot lose Freya.

Thea sits opposite me, sunglasses on, head lolling against the window, eyes closed. As we round a particularly sharp curve her head leans away from the glass and then thunks back with an aud-ible sound as the train straightens. She opens her eyes, rubbing the spot on her head.

‘Ow. Was I asleep?’

‘You were,’ I say shortly, not trying very hard to disguise the annoyance in my voice. I’m not sure why I’m irritated, except that I am so very tired myself, and somehow I can’t sleep. We didn’t go to bed last night until two or three, and then this morning I was up at six thirty with Freya. I haven’t had an unbroken night’s sleep in months, and I can’t sleep now, because Freya is slumbering in a sling on my chest, and I can’t relax in case I slump forward and crush her. But it’s not just that – everything feels edgy and heightened, and seeing Thea’s face relaxed feels like an insult to my own tense anxiety. How can she snooze so peacefully when everything is balanced on a knife edge?

‘Sorry,’ she says, pushing her fingers under the sunglasses to rub her eyes. ‘I didn’t sleep last night. Like, at all. I couldn’t stop thinking about …’ She glances over her shoulder at the sparse carriage. ‘Well, you know.’

I feel instantly bad. Somehow, I always misjudge Thea. She’s so much harder to read than either Fatima or Kate, she plays her cards close to her chest, but beneath her fuck-you exterior she’s just as frightened as the rest of us. More, maybe. Why can’t I remember that?

‘Oh,’ I say penitently. ‘Sorry. I haven’t been sleeping properly either. I keep thinking –’

But I can’t say it. I can’t voice my fears aloud. What if I get prosecuted? What if I lose my job? What if they take Freya?

I don’t dare say the words. Just saying them would make the possibility real, and that’s too terrifying to even think of.

‘Even if they find out –’ Thea breaks off, looks over her shoulder again and leans forward, closer to me, her voice barely audible. ‘Even if they find out that it’s him, we’re still OK, right? He could have fallen into a ditch after he OD’d.’

‘But so deep?’ I whisper back. ‘How could he have got so deep?’

‘Those ditches change all the time. You know that. Especially down by the Reach – that whole section has been eroded right back – the dunes are always shifting and changing. We didn’t –’ She glances again and changes what she was going to say. ‘I’m pretty sure it, the place I mean, was a good ten or twenty yards back from the shore, right?’

I think back, trying to remember. Yes … I remember the track was further back then, there were trees and bushes between us and the shore. She’s right.