Diane Fry had followed Maggie Crew as far as a long, narrow passage between the two sale rings. On one side were rows of steel pens packed with nervous calves; on the other side, a breeze-block wall was lined with plastic barrels of some dark liquid, stored for a later sale.

Maggie stopped and stared at her. ‘Well, you’ve done it in the end, Diane. Congratulations. You got under my skin, like a parasite I couldn’t get rid of.’

‘This is madness, Maggie. Put the knife down.’

Fry’s voice faltered as Maggie’s expression hit her like a bucket of freezing water. Though the sun that reached them through the high windows was weak and cold, its light was enough to change Maggie’s face. It clearly picked out the ragged edges of the scar tissue that ran across her cheek and into her hairline. The scar had flared angrily, marking her face like a fresh brand. Suddenly, Fry realized she was trapped in the narrow passage. They were alone among the rusted iron gates and the nervous cattle.

The knife in Maggie’s hand had a bright steel blade and a black hilt. Fry could see every detail of it – the markings on the handle, the narrow groove to channel the blood. Maggie held the knife out towards her, as if offering a treat for her to share.

‘We were going to use them to slash their tyres,’ she said. She smiled then – the first time that Fry had seen Maggie smile properly. But the corner of her damaged eye puckered and twisted her smile into a dreadful, ironic wink. ‘Ros would have been pleased.’

‘Do you mean Ros Daniels?’

‘Yes, Ros,’ said Maggie. ‘You knew about Jenny Weston too.’

Her grip tightened on the knife. Fry tensed, and her hand began to creep towards her scabbard, where the solid weight of her ASP sat, the foam grip protruding slightly, ready for her fingers to grasp.

‘When I was talking about Jenny Weston, it was because I wanted to make her a real person to you,’ she said. ‘Not just another victim.’

‘Oh, Jenny Weston was a real person to me,’ said Maggie. ‘But there was one thing you didn’t tell me about her. Was she my daughter’s lover?’

‘Your daughter?’

‘Yes – my daughter!’

Maggie’s shout reverberated around the tightly packed pens. The calves shrieked and scattered, crushing each other against the furthest corners of their steel cages. Fry’s hand slipped down to her scabbard. The handle of the ASP dropped into her palm and she flicked her wrist. With a hiss and a click of the ratchet, sixteen inches of steel baton suddenly shone in the artificial lights.

‘Stay back.’

Maggie grew calm again immediately. ‘Do you think you need that?’ she said. ‘You’re the great unarmed combat expert, aren’t you?’

‘How do you know that?’