I hear the front door slam and I look out of the window. Georgie and Jack are walking down the path. Georgie heads toward the common – she’ll be going to the station then on to Mayfair – while Jack gets into his black Saab. Part of me wishes I had asked to walk to the station with my sister. I would have felt a little safer. But then we would have had to get different trains – she, the Piccadilly Line to Green Park; me, the Thameslink to West Hampstead, where anyone could have got on and followed me. No, I think to myself as I step away from the window and unplug my phone, best to get a taxi.

I’m halfway down the stairs when I hear the letterbox clatter. I hurry down the last of the steps and see, lying on the doormat, a postcard.

I creep gingerly towards it, my skin prickling. When I see what it is I almost throw up. The picture on the front is a pencil drawing of Holly Maze House, complete with stone griffins and topiary animals.

I bend down to pick it up and as I turn the card over my body goes cold. There is no stamp, no postmark, just my name and six words, written in capitals.

ISN’T IT JUST TO DIE FOR?

There’s a loud knock on the door and I leap backwards, almost dropping the card.

This is it. He’s here. Connor. He’s come for me and I’m alone. What do I do?

My whole body begins to shake. Then my phone bleeps in my trouser pocket. I take it out. It’s a text from Uber. My taxi has arrived.

It’s okay, I tell myself. It’s just the taxi driver. Everything is okay.

I slip the postcard into my bag and open the front door.

The driver, a hawkish man with cropped black hair and narrow grey eyes, looks at me curiously as I climb into the back seat of the car.

‘West Hampstead police station, yeah?’ he says.

‘Yes, please,’ I say, shakily pulling the seat belt across me. I look at my watch – 10.20. I’ll be in West Hampstead in just under half an hour. It’s ridiculously early for my appointment but I figure I’d rather get out of the house than wait around and stew. I’ll find a coffee shop nearby where I can sit and gather my thoughts.

The driver nods his head but as the car pulls away I’m suddenly frozen with fear.

What if he is part of this? The car had arrived at the same time as the postcard came through the letterbox. What if he’s taking me somewhere else? What if …