She gestures to the huge seating area, which is larger than the average London flat. Plush moss-green velvet sofas surround a beautifully crafted bamboo coffee table, which is piled artfully with a spread of books and a vase overflowing with freshly picked hydrangeas.

‘You said you had three children, is that right?’

‘Oh yes,’ I say. ‘Two boys and a girl.’

‘How lovely,’ she says, smiling warmly. ‘I bet they keep you on your toes.’

‘I love them but they’re hard work; the boys are so naughty sometimes. That’s why I thought I’d make this trip alone,’ I say, running my hands over the soft velvet armchair. ‘But my little Lavender is an angel, and I wouldn’t swap any of them for the world.’

‘I bet they’d love the space to run around here,’ the estate agent continues, selling this idyllic place to me even though my heart already knows what it wants.

‘Oh yes, Freddie would go mad with all this space to play football and Barclay would run wild and most likely break an arm like he did on his ninth birthday last year! He’s forever getting into trouble,’ I chuckle.

‘Imagine the birthday parties you could give them here,’ she says, unlocking a side door that leads out to a sweeping stone terrace.

I step outside and breathe in the crisp morning air. As I stand on the terrace the air fills with children’s laughter. I see trestle tables groaning with party food, guests bearing brightly coloured parcels, music filtering out from the kitchen, balloons and bunting and candles on a cake, birthday wishes to be made.

‘It’s perfect,’ I whisper as the estate agent leads me back into the house. ‘Just perfect.’

But as we walk back through the living room and head towards the hallway, a chill ripples through me. What would Connor say if he could see me?

‘Now,’ says the estate agent, consulting her brochure. ‘Let’s show you the first floor, shall we, Imogen?’

I nod my head.

If only you knew, I think to myself as I follow this poor, unsuspecting young woman up the winding staircase. That there are no children, no birthday parties, no prospect of a commission. That Imogen isn’t even my real name. That all this is a perfect lie.

PART ONE

1. Now

Wimbledon, South West London August 2018

I sit in my sister’s living room, sipping coffee from a cup that says MUM, though I have no children to call my own, my eyes transfixed by the laptop screen in front of me. I know I shouldn’t have logged on, know that this addiction will be the ruin of me, but nothing else will help tonight, nothing else will stop the dark thoughts invading or stem the fear that is creeping like poison through my body.