I go downstairs. ‘Hugh?’

He’s sitting in the living room with a glass of whisky. I sit down opposite him.

‘You should go to bed.’

‘I’m sorry.’

He looks at me, for the first time since I came into the room. He sighs, sips his whisky.

‘It hurts.’

‘I know.’

There’s nothing else to say. We go to bed.

In the morning I talk to Connor.

‘I don’t know what you heard last night,’ I say. ‘But your father and I love you very much.’

He’s sloshing milk into his cereal bowl and some spills on the table. I resist the urge to dab it dry. ‘I just heard you arguing.’

It feels like a slap. It’s the very opposite of what I want for my son, of what I promised Kate. Stability. Loving parents. A home free of conflict.

‘All couples argue. It’s normal.’

‘Are you going to split up?’

‘No! No, of course not.’

He goes back to his cereal. ‘What were you arguing about?’

I don’t want to tell him.

‘It’s difficult. The last few months have been tough. On all of us. With Auntie Kate, and everything.’ I know I’m stating the obvious, but it feels true, and necessary. A shadow crosses his face and for an instant I see how he’ll look when he’s much older, but then it passes, leaving a kind of sadness. I think he’s going to say something, but he doesn’t.

‘Do you miss her?’

He freezes, his spoon midway between the bowl and his mouth. He puts it back. Again he looks thoughtful, much older. For some reason he reminds me of Marcus – it’s the same expression he had when on those rare occasions he was worried or pensive – but then he speaks and becomes a teenager once again.

‘I don’t know.’ His face collapses, tears come. It’s unexpected and I’m swept to my feet in an urge to soothe and comfort.

‘It’s okay. Whatever you feel, or even if you don’t know, it’s okay.’

He hesitates. ‘I suppose I do miss her. A bit. Do you?’

‘Yes. Every day.’

‘I mean,’ he goes on, ‘we didn’t see her that often, but still …’

‘It’s different, isn’t it?’

‘Yes. When someone is alive you might not see them very much, but you know you can. If you want.’

‘Yes.’

‘And now I can’t.’

I remain silent. I want to give him the time to speak, but also I’m wondering whether he really had felt that he could see his mother. Hugh and I may have given him permission if he’d asked – to do that, to go and stay with her – but we had never really encouraged it. Maybe I was too frightened that she wouldn’t let him come back.

‘You know,’ I say eventually, ‘whatever you’re feeling, you can ask me about anything. Anything at all.’

Even though I mean it, my words sound hollow. Because the truth is, there are secrets, things I won’t tell him, even if he asks.

There’s a long pause, then he asks, ‘Do you think they’ll get them? The people who killed Kate.’

It stops me in my tracks. He hasn’t called her Auntie. I wonder if it’s the first step on the path to calling her Mum. The air between us crackles.

‘I hope so, darling. But it’s difficult.’

There’s a silence between us.

‘Dad says she was a nice person who fell in with a bad crowd.’

I press some bread down into the toaster and look up. I smile. That’s exactly what Hugh used to think of me. A nice person, over-influenced by those around me. He would tell me, while I was in Berlin, ‘Look after yourself,’ he’d say, ‘We all miss you …’, and I knew he meant, Those people aren’t your friends. He was trying to save me, even then; I just wasn’t ready to be saved.

‘She was a really lovely person. Full stop.’

He hesitates.

‘So, why didn’t she want me?’

‘Connor,’ I begin. ‘It’s complicated—’

‘Dad says I shouldn’t worry about it. He says that Auntie Kate loved me very much but she wasn’t coping, that she couldn’t afford a baby, but you could, so it made sense.’

‘Well, that’s really a very simplistic way of looking at it …’

I wonder when Hugh’s been telling Connor all this. I didn’t even know they’d talked. I tell myself we need to make more of an effort, to be upfront with Connor, to be united. Like we’d decided years ago.

‘If you wanted children, why didn’t you have one?’

‘We couldn’t.’ I’m trying to keep my voice even; I don’t want it to crack, to betray how much loss I contain. ‘We’d been trying. For several years. But one of us …’ I stop. He doesn’t need the details. ‘We just couldn’t.’ It comes to me, then. The clinic: white walls and rubber floors, boxes spilling blue gloves, posters advertising helplines and charities that I knew I’d never call. I remember the stirrups, the cold metal between my legs. It felt like a punishment.

I realize I’ve still never told anyone about that, certainly not Hugh. He doesn’t know anything about that baby I could have had but didn’t.

‘Who couldn’t?’

I look at my son. At Kate’s son. ‘I don’t know.’ The familiar sense of shame comes, then. I thought I’d conquered it, years ago. I was mistaken. ‘We don’t know. But it doesn’t matter. It makes no difference. We love you, Connor. You’re our son.’

The toaster pings, the bread pops up. I’m startled, briefly, then I begin to butter his toast.

‘Thanks, Mum,’ he says, and I’m not sure what he’s thanking me for.

I take the key from my bag and unlock the padlock. The shed door swings inwards with a creak and I wait for a few moments to let some of the heat out before stepping in. Even though the walls are lined and painted and I light scented candles in here when I work, it still smells vaguely of wood. Yet it’s comforting; my own space, a refuge.

I close the door behind me and sit at the desk. I put the biscuit tin in front of me, the one Anna gave me. I feel calmer, now. I know what I have to do.

I take Kate’s Filofax out of the tin and put it on the desk, next to my laptop. The light that streams into my studio through the window behind me reflects off its surface and I adjust my chair and change the angle of the screen. Finally I press a key.

My background picture is an old photo of me, sitting on a bench on the Heath with Connor on my lap. In the photo he’s four, maybe five. A decade ago, and I look so happy, so excited finally to be a parent, yet now it feels as if it belongs to a different time completely. I realize once again how Kate’s death has sliced my life in two.

I press another key and the picture of Connor disappears, replaced by the last window I’d had open. It’s a video.

I press play. It’s a film of the two of us, me and Connor, on a beach. Hugh took it, years ago, back when he still used his camcorder. Connor is about five, dressed in red trunks and slathered in sunblock, and the two of us are running away from the camera, into the sea, laughing as we do.

It was a glorious summer; we’d hired a villa in Portugal. We spent the days by the pool, or on the beach. We had lunch in a restaurant in the village, or we’d take a drive into the hills. We sat on the terrace and watched the sun go down after we’d put Connor to bed. We’d sit, and talk, and then we’d go to bed ourselves, where, quietly, carefully, we made love. We were happy. So very, very happy.

The video is almost over when I get a call; it’s Anna, on Skype. I don’t want to talk to her now. I click ignore. I’ll call her back later. What I have to do won’t take long.

The video finishes; Connor is frozen in the distance.

I’m ready.

I open my browser and begin to type the web address: encountrz. I only have to type the first few letters; the rest autofills from the night before last, the time I hadn’t got as far as pressing enter.

I press it now. I have a sense of weightlessness; it’s inexplicable, but real. My body has become unmoored. I’m floating. The window loads. A photo appears, a couple, walking along a beach, laughing. It looks somehow banal, but what had I expected?

At the top of the screen is a box marked ‘Username’, and another headed ‘Password’. I type in ‘KatieB’, then ‘Jasper1234’. I select enter.