There’s a quiet crunching noise and the door swings opens. Thank goodness the whole door didn’t crash to the ground.

I step into a warm, dim room, my heart pounding in my ears. I have just broken into a stranger’s house.

Judging by the clothes hanging on a line next to me, I’m in a laundry. I take off my boots and enter a huge, dark kitchen. The tiled floor is warm. Imagine that, they must heat the actual floor.

In the light coming from the oven clock, I can see a bowl of fruit on the bench, and half a cake under a glass dome. I’m here, Mum. I’m here, I think. Can she smell me now?

A clock chimes somewhere in the house. It’s four in the morning. We have thirteen hours to get back to London.

There’s a clicking behind me and I spin around to see a scruffy black-and-white dog approaching, wagging her tail.

‘Hello, doggo,’ I whisper and bend to pat her. ‘You’re not a very good guard, are you?’ But dogs never bark at me.

She follows me up the wide carpeted stairs. At the top is a big landing, and I’m wondering which of the open doors to look in when I hear a toilet flush.

There’s no time to run back downstairs. I crouch on the stairs and make myself as small as possible, hot with the terror of being caught in this family’s house. What was the cloak of darkness spell?! Rho glogyn something.

‘Where have you been, Mabli?’ says a woman. She’s on the landing, just a few metres from me. I’m scrunched up, holding my breath.

‘Come with me, girl,’ she says, and disappears into one of the rooms. I hear the rustle of bed clothes, then everything is silent.

Mabli reappears after a minute and nudges me for a pat. What if the woman comes looking for her? I crouch there for what feels like half an hour, then creep silently across the landing.

Where would a nanny sleep? With the children? Might she be in one of those rooms?

In one room, a child about the age of Kit’s twin sisters is sprawled sideways on a four-poster bed. In the second room a girl sucks her thumb beside a fairy nightlight. Further down a hall, I find two older children in a bunk bed.

‘Who are you?’ says a small voice behind me.

I nearly shout with fright.

It’s the kid who was sucking her thumb. She looks about three or four. It’s hard to see her face in the dim light, but she has a wild mop of hair.

‘Hello,’ I whisper, and crouch down, my heart pounding. ‘I’m Tulsi. Who are you?’ Please don’t call out to your mum, I think. What on Earth will I say if the girl’s mother appears?