‘Jimmy Perez, you never fail to surprise me.’

They left the car where it was and walked towards the old croft house. It was mid-afternoon and suddenly still and humid, with the smell of flowers from the in-bye land that was no longer grazed or cultivated. He was reminded of Fair Isle and wondered when he’d be brave enough to take Cassie to see where her mother had died. He’d promised they’d go before the end of the school summer holidays and he hadn’t yet broken a promise to her. He’d wait for a still day like this, and they’d sail in from Grutness with his father at the helm of the Good Shepherd, so that Cassie could sit out on deck and watch the island get closer.

Willow was walking ahead of him and waited for him by the door. ‘Well,’ she said. ‘What brought Charles Hillier to this place the day that he died?’

‘Money.’ Once the word was spoken it was obvious to him. ‘He and David might not have had a conversation about how hard up they were, but both must have known that the business was failing. And they were desperate.’ He imagined the men skirting around the subject, not wanting to face the difficult decisions that would have to be made, trying to be kind and not to blame the other.

‘You think he might have tried his hand at blackmail?’

‘Maybe.’ But Perez had other ideas swirling around in his head.

‘The English people all had the money to pay up,’ Willow said. ‘But what could Charles have that might hold them to ransom? Eleanor’s digital recorder? All it tells us is that Vaila Arthur was telling the truth about being interviewed. And that a child sang a song about Lizzie Geldard to Eleanor Longstaff before she died.’

‘Perhaps it wasn’t the recorder at all.’ Out at sea a flock of gulls followed a small fishing boat. ‘Perhaps it was information. Perhaps he knew who’d committed the murder of Eleanor Longstaff.’

‘He saw her being killed, you mean?’

‘Or saw enough to guess.’ Perez still wasn’t sure how that might work out.

‘So you think Charles had arranged to meet someone here?’ Willow opened the door of the old house, but remained outside. Perez smelled damp stone and peaty soil. ‘And Polly and Ian disturbed him?’

‘It’s possible.’ In his mind he was running through a theory that seemed at once too elaborate and too simple.

‘Shall we bring Vicki Hewitt back? See if we have evidence of a fourth person in the place?’

He was about to speak when there was a noise inside, something scrabbling and clawing, and a cry, piercing like a child’s. Willow was about to go in, but he put his hand on her arm to stop her, and a creature shot past them.