‘You don’t have to do this,’ he said gently. ‘The longer old pain has been buried, the harder it is to dig up.’

‘But you shouldn’t leave someone as beautiful as Emily Drennan buried in a cellar, should you?’ said Nikki. ‘She deserves to be brought into the light.’

And thinking about those words, Nikki steeled herself, and slipped back into the past.

‘Is there anyone there?’ Her voice echoed back to her from the high, cavernous basement of the old warehouse. ‘It’s the police. I’m here to help.’

At first she heard nothing, except the dripping of water and the occasional scurrying of a rat. Then she caught the faint sound of a sob. Picking her way carefully through the debris of the deserted building, she moved towards the area where the sound had come from. ‘Don’t be afraid. I won’t hurt you! Can you hear me?’

The sobbing was getting louder, but swinging her torch beam around, Nikki realized that she was walking beneath dangerously rotting timbers. The floor above had collapsed in several places, leaving splintered wood and chunks of masonry everywhere. Perhaps shouting loudly was not such a good idea.

Nikki stopped to get her bearings, and looked around. Shafts of late evening sun were filtering in from the ground floor, through the gaping holes, and into the cellar. They criss-crossed the dark, gloomy basement like a giant cat’s cradle of golden light. If it were not so treacherous, it might have been beautiful.

‘Over here.’ The voice was tremulous and weak.

Nikki sprang forward. ‘Where are you? Are you badly hurt?’

For a second she thought she heard a laugh. But it was not a happy laugh, or a laugh of relief that help was finally at hand. It was a sound that made Nikki’s blood run cold, and a sound she was to hear for years to come, in the dead of night, when sleep evaded her.

‘Help me.’ It was a girl’s voice.

‘I’ll get help, don’t worry.’ Nikki pulled herself around a pile of broken brickwork, and saw her.

The girl was laying, curled up in the foetal position, in the dirt and rubbish on the cellar floor. One ankle was twisted in an unnatural position away from her body, but she didn’t even seem aware of it. She cried softly, whispering one name, over and over: Stevie, Stevie, Stevie.

‘You’re safe now, sweetheart,’ Nikki dropped down beside her. ‘Can you tell me your name?’

‘Stevie? Oh, I knew you wouldn’t leave me.’ The voice was little more than a hushed sigh.

Nikki tried her radio but couldn’t get a signal. ‘I’ve got to find a spot where my radio works, you just hold on. I’ll be back, okay?’

She scrambled towards one of the holes in the ceiling, and managed to get a weak, stuttering message across for an ambulance and some assistance.