‘What happened to the drawings?’ Thea asks.

‘The ones the school found? I’m pretty sure they were destroyed. I can’t imagine Miss Armitage wanted them found any more than we did.’

‘And the others?’ I ask. ‘The ones Ambrose had here?’

‘I burnt them.’ Kate says it with finality, but there’s something about her eyes, the way her gaze flickers when she says it, I’m not absolutely certain she’s telling the truth.

It was Kate who salvaged the situation – as far as it could be salvaged – back at school. When she turned up on Sunday afternoon, pale but composed, Miss Weatherby was waiting, and Kate was marched straight into the headmistress’s study, and didn’t come out for a long time.

When she emerged, we flocked around her, our questions beating at her like wings, but she only shook her head, and nodded towards the tower. Wait, her nod said. Wait until we’re alone.

And then, at last, when we finally were alone, she told us, while she packed her trunk for the last time.

She had said that the drawings were hers.

I have no idea, even today, whether Miss Armitage believed her, or whether she decided, in the absence of concrete proof to the contrary, to accept a fiction that would create the least fallout. They were Ambrose’s sketches, anyone with an eye for art could have told that. Kate’s style – her natural style at any rate – was completely different – loose, fluid, with none of Ambrose’s fineness of detail.

But when she wanted, Kate could imitate her father’s style to perfection, and perhaps she showed them something that convinced them – made a facsimile of a sketch in the office, maybe. I don’t know. I never asked. They believed her, or said they did, and that was enough.

We had to go – there was no question of that. The breaking out of bounds, the alcohol and cigarettes in our room, all of that was explosive enough – grounds for expulsion, certainly. But the pictures, even with Kate’s confession, the pictures added a dose of nuclear uncertainty to the whole thing.

At last, the unspoken pact was arrived at. Go silently, without expulsion, was the message, and pretend the whole affair never happened. For all our sakes.

And we did.

We had finished our exams, and it was only a few weeks until the summer vac started, but Miss Armitage wouldn’t wait for that. It was all over astonishingly fast – within twenty-four hours, before the end of the weekend, we were gone, all of us, first Kate, packing her belongings into a taxi with white-faced stoicism, then Fatima, pale and tearful in the back of her aunt and uncle’s car. Then Thea’s father, excruciatingly loud and jovial, and finally mine, sad and drawn beyond all recognition almost.

He said nothing. But his silence, on the long, long drive back to London was almost the hardest to bear.

We were scattered, like birds – Fatima got her wish, at last, and went out to Pakistan where her parents were finishing up their placement. Thea was sent to Switzerland, to an establishment halfway between a finishing school and a remand home, a place with high walls and bars on the windows and a policy against ‘personal technology’ of any kind. I was packed off to Scotland, to a boarding school so remote it had once had its own railway station, before Beeching closed it down.

Only Kate stayed in Salten, and now, it seems to me, her home was as much a prison as Thea’s finishing school, except that the bars on the window were of our own making.

We wrote, weekly in my case, but she answered only sporadic-ally, short, weary notes that spoke of an endless struggle to make ends meet, and of her loneliness without us. She sold her father’s paintings, and when she ran out she began to forge them. I saw a print in a gallery in London that I know for a fact was not one of Ambrose’s.

All I knew of Luc was that he had gone back to France – and that Kate lived alone, counting down the weeks until she turned sixteen, fending off the endless questions about where her father had gone, what he had done, and realising that slowly, slowly his very absence was turning the vague suspicions of wrongdoing into hardened certainty of his guilt.

We wrote, on her sixteenth birthday, each of us, sending our love, and this time at least she wrote back.

‘I am sixteen,’ she wrote in her letter to me. ‘And you know what I thought, when I woke up this morning? It wasn’t presents, or cards, because I didn’t have any of those. It was that I can finally tell the police he’s gone.’

WE MET UP only once more, all of us, and it was at my mother’s funeral, a grey spring day in the year I turned eighteen.

I was not expecting them. I hoped – I couldn’t deny that. I had emailed and told them all what had happened, and the date and time of the funeral, but without any kind of explanation. But when I turned up at the crematorium in the car with my father and brother, they were there, a huddle of black in the rain, by the gate. They lifted their heads as the car made its slow way up the crematorium drive, following the hearse, such sympathy in their eyes that I felt my heart crack a little, and suddenly I found my fingers numbly scrabbling for the door handle, heard the crunch of tyres on gravel as the driver stamped hurriedly on the brake, and I stumbled from the car.

‘I’m so sorry,’ I heard the driver saying, ‘I would have stopped – I had no idea she –’

‘Don’t worry.’ My father’s voice was weary. ‘Keep going. She’ll make her own way up.’

And the car engine roared into life again, and disappeared up the drive into the rain.

I can’t remember what they said, I only remember the feel of their arms around me, the cool of the rain, dripping down my face, hiding the tears. And the feeling that I was with the only people who could fill the gaping hole that had opened up inside me, that I was home.

It was the last time the four of us would be together for fifteen years.

‘DOES HE KNOW?’ Thea’s voice, croaky with smoke, at last breaks through the silence of the room where we have been sitting, and thinking as the candles burnt low in their sockets and the tide outside swelled to its height and then slowly retreated.

Kate’s head turns, from where she has been staring out at the quiet black waters of the Reach.

‘Does who know what?’

‘Luc. I mean, he clearly knows something, but how much? Did you tell him what happened that night, what we did?’

Kate gives a sigh, and stubs out her cigarette in a saucer. Then she shakes her head.

‘No, I didn’t tell him. I never told anyone, you know that. What we – what we –’

She stops, unable to finish.

‘What we did? Why not say it?’ Thea says, her voice rising. ‘We concealed a body.’

It’s a shock, hearing the words so baldly spoken, and I realise that we have been skirting round the truth of what we did for so long that hearing it aloud is like a kind of reality check.

For that is what we did. We did conceal a body, although that’s not how the courts would phrase it. Preventing the lawful and decent burial of a body would likely be the offence. I know the wording, and the penalties. I have looked it up enough times under cover of checking something else, my fingers shaking every time I read and reread the words. Possibly also disposing of a body with the intent to prevent a coroner’s inquest, although that made me give a little, bitter laugh the first time I came across the phrase in the law journals. God knows, there was no thought in our head of a coroner’s inquest. I’m not sure I even knew what a coroner was.

Was that part of the reason I went into law, this desire to be armed with the knowledge of what I had done, and the penalties for it?

‘Does he know?’ Thea says again, banging her fist on the table with each word in a way that makes me wince.

‘He doesn’t know, but he suspects,’ Kate says heavily. ‘He’s known something was wrong for ages, but with the newspaper reports … And on some level he blames me – us – for what happened to him in France. Even though it’s completely irrational.’

Is it? Is it really so irrational? All Luc knows is that his beloved adoptive father disappeared, that a body has surfaced in the Reach, and that we have something to do with it. His anger seems very, very rational to me.