‘Joe, listen,’ I say, edging closer to him. ‘We’re definitely going to see Daddy soon but first we have to enjoy our lovely holiday.’

‘Not holiday,’ he cries, his eyes widening. ‘There’s no sand.’

I smile as I remember that trip to southern Spain. Joe dipping his toes into the sea for the first time, giggling as the waves came in.

‘No,’ I say. ‘There’s no sand here but there’s a lovely lake and lots of …’

I stop myself. Here I am trying to reassure my little boy about this place when all I can think about is Mark standing at the window.

‘Joe, do you remember what happened last night?’ I say, trying to keep my voice light. ‘Before we went to sleep.’

He shakes his head.

‘You said you saw Daddy at the window,’ I say, a shiver rippling down my spine as I say those words.

‘Daddy?’ he exclaims, his face lighting up. ‘Daddy’s here?’

‘No, he’s not here now,’ I say, peering behind me into the dark corridor. ‘But last night you woke up and said that you could see Daddy outside the window. He was making you giggle. Do you remember?’

‘No,’ says Joe, wrinkling his nose. ‘Don’t ’member. Will you get my breakfast now?’

‘Of course,’ I say, getting to my feet and taking him by the hand. ‘Let’s go see what we can find.’

It was a dream, I tell myself as we head to the kitchen. Joe was talking in his sleep. I used to do that all the time when I was young and it would scare the life out of my parents. My mum told me how she’d once come into my bedroom to say goodnight and found me sitting up in the bed with a demonic look on my face. When she asked if I was all right I asked her, in a very low, frightening voice, if she wouldn’t mind opening the wall with the secret key. Mum said I looked like I’d been possessed but apparently I continued to do this for years right up until my teens. When she looked into it she found that some people suffer from waking nightmares, where they look awake but are still asleep and carrying on the dream as if in real time.

That must have been what happened with Joe last night, I tell myself as I fill the kettle with the last bit of lake water from the jug. He was dreaming. Mark wasn’t at the window. Of course he wasn’t. Yet the more I tell myself this, the more I think about the footsteps and the car engine, and the less I believe it.

‘Now, Mr Joe,’ I say as I light the stove and put the kettle on to boil. ‘How do you fancy a lovely bowl of porridge?’

I turn round. He’s not at the table.

‘Joe,’ I call, running into the hallway. ‘Where are you, Joe?’

He’s not in the living room. Maybe he’s gone back to bed. I try to stem the fear that is rising up inside me as I walk back down the corridor, past the dark staircase, towards the bedroom.