Cooper was due to meet Liz in the market square, but he was early when he left the flat. So he took his time and walked down to the river to reach the town centre. Just before the Eyre Street bridge, he stopped at the weir to watch the ducks, a crowd of mallards fussing about in the darkness, splashing under the trees.

Above their noise, he thought he heard a familiar voice behind him.

‘Ben?’

He turned in surprise. ‘I thought you were in –?’

And then he saw that he’d been mistaken. It was Angie Fry who stood in front of him, much as she’d once stood on his doorstep in Welbeck Street. She wore the same anorak and even carried the same battered rucksack over her shoulder.

‘Angie. Are you going somewhere?’

She didn’t answer, perhaps thinking it a stupid question. She had never seemed to have much respect for his intelligence.

‘Always the ace boy detective, Constable Cooper.’

Cooper swore at that moment that he wasn’t going to let Angie Fry use him again for her own purposes.

‘What do you want, Angie? I’m busy.’

‘Sure. Communing with the wildlife.’

Anxiously, Cooper looked over his shoulder. The lights of the market square were just ahead, only a few yards away. He could see people passing under the illuminated Christmas trees and the flickering reindeer strung across Eyre Street.

‘I won’t keep you long from your date,’ said Angie with a smirk.

‘How did you know –?’

Angie pulled an envelope from a pocket of her anorak. ‘I need to give you this.’

‘What is it?’

‘Information. I promise you’ll find it interesting.’

‘You should give it to Diane.’

‘She’s away.’

‘Yes, in Dublin,’ said Cooper. ‘But she’ll be back tomorrow.’

Angie just looked at him, holding out the envelope. She seemed so much like her sister as she stood with her back to the light, shadows hiding the difference in her features, the anorak concealing her narrow shoulders, and the almost skeletal thinness of her arms – all the things Cooper remembered being struck by when he’d first met her.

He took her silence for communication. ‘I understand. You won’t be seeing Diane tomorrow, will you?’

‘No.’

Reluctantly, Cooper took the envelope. ‘Angie, are you going away again?’

Angie shifted the straps of her rucksack until they were more comfortable. ‘You’ll find information in that envelope about the current location of the crystal meth lab that supplies Sheffield. It’s in your area. I believe it’s operated by a group who took over supply when the lab at Rakedale closed down.’

Cooper was stunned. ‘How did you get this?’

But Angie shrugged. ‘I’ve been working with people who have this sort of information. They’ve been letting the lab continue to operate, for their own reasons, and I don’t agree with it.’

‘What people are you talking about?’