‘They didn’t come through here,’ Chan said. There was a large window to the left. At some point the glass had been broken and it had been covered with a board. ‘And I don’t think they got in there, either.’

They walked down the side. There were a series of high windows at least thirty feet above the ground. At the far end was a loading bay. It too was secured with a padlocked chain. Wynne picked up the padlock. She pulled it; it was locked.

‘Not here either,’ she said. She looked down the other wall of the building. There was a door about halfway along.

‘Let’s check that out,’ Wynne said.

They walked along the building. The door was metal, and had the words ‘Fire Escape’ printed on it in faded red letters. There was no chain, and no padlock.

Chan glanced at Wynne. He walked up to the door and gripped the handle. It twisted and the door swung open.

‘Get an officer,’ Wynne said. ‘I want backup.’

Martin

Sandra was lying on the bed. There was a cup of tea and a packet of biscuits on the table next to her. As the door opened, she looked at Martin.

The whole of his life seemed to crystallize in that moment. There were two possible futures, the left fork of illness and treatment and maybe the premature loss of his wife and the right fork of good health – for now, at least – and travel and growing old together.

And then there was Maggie. He didn’t dare believe it yet, but if she was alive and Wynne could find her, what would she come home to? Would she be reunited with her mum, only to lose her again? It seemed impossible that the universe could be so cruel, but Martin had learned from bitter experience never to underestimate the capacity of the universe for cruelty.

He took a step into the room.

‘So?’ he said.

Sandra smiled.

‘It’s OK,’ she said. ‘I’m clear. I guess it really was just an upset stomach.’

Wynne

There were no lights, but in the beam of the torches they could see that the building was empty. It was a warehouse of some description, and, apart from a thick layer of dust, an unpleasant, animal smell and a stack of pallets in the far corner, there was nothing.

‘There are offices at the front,’ Wynne said. ‘Where the reception is. Check those.’

Two officers – a man and a woman – headed for the front, their torches bobbing in the darkness. It was not long before they called out that there was nothing – and nobody – there.

Wynne and Chan walked out into the sunshine.

‘Not in that building,’ Chan said.

‘There are three more,’ Wynne said.

‘I know.’ Chan looked around. ‘But there’s no one here. No one’s been here for years. You can tell.’

‘You can’t be sure.’