I dragged my gaze from the dogs and stared where she was staring. The building opposite had a strange, zigzag roof and it was locked, a heavy-looking chain and padlock keeping the doors tightly shut, but the door of the building that the dog was chained to stood open a few inches. In and out of the opening buzzed hundreds and hundreds of flies.

‘What’s in there?’ Emma whispered.

‘I don’t know,’ I murmured, turning to the small house.

The door was painted dark green and the paint was peeling. A brass door knocker in the shape of a horse’s head stared at me. Next to the door on the wall of the house, scrawled in black pen, were the words Knackers Yard. I hesitated, then raised my hand and banged the horse head three times. We waited, Emma’s hand trembling ever so slightly in mine. Clouds blocked the sun, pooling us in shadow. I knocked again. Louder, more urgently, straining my ears for the sound of footsteps behind the door.

‘Let’s go,’ Emma whined.

‘No,’ I said, knocking a third time.

‘Hello!’ I called.

I tried the door, barely touching the doorknob, and the door swung inward with a long, high-pitched creak. I took a tentative step forward and peered into the gloomy interior of the house.

‘Hello?’ I tried again.

‘Maybe we can find a telephone,’ Emma said, her voice smaller than ever.

I looked at her. Mother didn’t own a telephone but I knew from my books that lots of people did. ‘Yes – where will it be?’

‘What?’

‘The telephone?’

‘We keep ours in the lounge at home.’

‘OK, great. So if we can find a phone, we can talk to someone who might help us. We can call the police.’

Emma nodded. ‘Yes. The numbers are nine, nine, nine. Mummy and Daddy teached me them.’

‘That’s brilliant,’ I said smiling at her. ‘Come on.’

I pulled her into the house, leaving the door open behind us. We were in a small kitchen. The counters were a mess; covered with dirty plates and dirty saucepans and mugs, filling the room with an unpleasant smell a bit like sour milk. I flicked a light switch but it didn’t come on.

‘The telephone won’t be in here,’ Emma said.