‘Well …’ I put my hand in my pocket, and I draw it out – an envelope, with Kate’s name on it, very old and much folded, and now salt-stained and water-marked as well.

It is readable though – just. The biro ink has bloomed, but not washed away, and you can still make out Ambrose’s words to his daughter: Go on: live, love, be happy, never look back. And above all, don’t let this all be in vain.

Only now it feels like he is speaking to us.

THE TAXI DROPS us off on the promenade at Salten, and as Fatima pays the driver, I get out and stretch my legs, looking not towards the police station, squat and concrete next to the seawall, but out – towards the harbour and the sea beyond.

It is the same sea that greeted me at the window of my room at Salten House, the sea of my childhood, unchanging, implacable, and that thought is somehow reassuring. I think of all that it has witnessed, and all that it has accepted into its vastness. The way that it is taking the ashes of the Tide Mill back for its own – Kate and Luc with it. Everything we did – all our mistakes, all our lies – they are being slowly washed away.

Thea appears at my elbow, looking at her watch.

‘It’s nearly four,’ she says. ‘Are you ready?’

I nod, but I don’t move.

‘I was thinking,’ I say, as Fatima steps back from the cab, and it pulls away.

‘About what?’ she asks.

‘About …’ The word comes to me almost unbidden, and I say it with a sense of surprise. ‘About guilt.’

‘Guilt?’ Fatima’s brow furrows.

‘I realised, last night, I’ve spent seventeen years thinking that what happened with Ambrose was our fault, in a way. That he died because of us – because of those drawings, because we kept coming back.’

‘We didn’t ask to be drawn,’ Fatima says, her voice low. ‘We didn’t ask for any of this.’

But Thea nods.

‘I know what you mean,’ she says. ‘However irrational it was, I felt the same.’

‘But I realised …’ I stop, feeling for the right words, groping to pin down a realisation only half formed in my own mind. ‘Last night, I realised … his death was nothing to do with that. It was never about the drawings. It was never about us. It was never our fault.’

Thea nods slowly. And then Fatima links arms with both of us.

‘We have nothing to feel ashamed of,’ she says. ‘We never did.’

We are turning to walk towards the police station when a figure comes out of one of the narrow twittens that wind between the stone-built houses. A massive figure, swathed in layers of clothes, with an iron-grey pigtail that flutters in the sea breeze.

It is Mary Wren.

She stops when she sees us, and then she smiles, and it is not a pleasant smile – it’s the smile of someone who has power, and intends to use it. And then she begins to walk across the quay towards us.

But we begin to walk too, the three of us, arm in arm. Mary changes her course, ready to cut us off, and I feel Fatima’s arm tighten in mine, and hear the pace of Thea’s heels on the cobbles quicken.

Mary is grinning now, as we draw closer, her big yellow teeth bared, like a creature ready to fight, and my heart is thumping in my chest.

But I meet her gaze, and for the first time since I came back to Salten I am without guilt. I am without fear. And I know the truth.

And Mary Wren falters. She breaks stride, and the three of us push past her, arm in arm. I feel Fatima’s arm, firm in mine, and I see Thea smile. The sun breaks through the clouds, turning the grey sea bright.

Behind us, Mary Wren calls out something inarticulate.

But we keep walking, the three of us.

And we do not look back.

THERE IS A story I will tell Freya when she is older. It’s the story of a house fire, an accident caused by faulty wiring, and a lamp knocked over in the night.

It’s the story of a man who risked his life to save her, and my best friend, who loved him, and went back for him when she knew it was hopeless.

It’s a story about bravery, and selflessness, and sacrifice – about a father’s suicide and his children’s grief.

And it’s a story about hope – about how we have to go on, after the unbearable has happened. Make the most of our lives, for the sake of the people who gave theirs.

It’s the story that Thea, Fatima and I told Sergeant Wren when we went to the station, and he believed us, because it was true.

It’s also a lie.

We have been lying for almost twenty years, the three of us. But now, at last, we know why. Now at last, we know the truth.

It is two weeks later and, once again, Freya and I are on a train, to Aviemore this time, almost as far from Salten as you can get without crossing the North Sea.

I think about the lies I have told, as the train hurtles north, and Freya sleeps in my arms. I think about those lies, the lies that poisoned my life and my relationship with a good and loving man. I think about the price that Kate paid for them, and how they put Freya in danger, and my fingers tighten on her, so that she stirs in her sleep.

Perhaps it is time to stop lying. Perhaps … perhaps we should tell the truth, all of us.

But then I look down at Freya. And I know one thing – I never, never want her to have to go through what I did. I never want her to have to check a story against the lies that she has told, testing it for holes, trying to remember what she said last time and guess what her friends might have told.

I never want her to have to look over her shoulder, to protect others.

I think about the sacrifice that Ambrose made for Kate, for Luc, and I know – I will never tell Freya the truth. Because to do that would be to pass on my burden to her.

I can do this. We can do this, Fatima, Thea and I. We can keep our secrets. And I know they will do it. They will stick to the story we cooked up in whispers in our bedrooms at the B&B – of vague timings and mutual alibis. It’s the last thing we can do for Kate, after all.

My phone bleeps around York, making Freya stir in my arms before she settles. It’s Owen.

How’s it going – did you make the train ok?

I have been thinking of him, all journey. Of how he looked when I waved him goodbye this morning as Freya and I set off to King’s Cross.

And further back, to the way his hands were trembling when he got out of the car in the car park of the B&B at Salten, the way he took Freya in his arms as if they’d been apart for weeks, as if he’d have swum an ocean to save her. He pressed his lips to the top of her head and when he looked up, there were tears in his eyes.

And further back still, to the light that seemed to illuminate him from within when he held her that very first time, the night she was born. He looked down at her face, and up at me with a kind of wonder, and I knew then what I know now – that he would walk through fire for her.

I take a breath and hold it for a long time, looking down at Freya’s slumbering face. And then I text back.

Everything’s fine. Dad’s meeting us at Aviemore. I love you.

It’s a lie, I know that now. But for her, for Freya, I can keep lying. And maybe one day I can make it true.