‘It’s almost mathematical,’ Simon muttered. ‘Three twos. But also … two threes.’

‘Any chance you could relocate your cryptic pondering to the kitchen? For once, a meal I’ve produced looks quite tempting. I must have taken the lid off the pesto jar differently.’

Simon stayed where he was.

‘Okay, well, I’m going to the kitchen to eat. See you when I see you.’ Halfway there, Charlie stopped and turned back. ‘What threes?’ she asked.

‘Linzi Birrell, Josh Norbury and Kim Tribbeck. Billy’s punished them all – or wants to punish, in the case of Kim – for the same crime.’

‘And his other three victims: Rhian, Angela, Marion?’

‘Same. Rhian Douglas, Angela McCabe and Marion Hopwood – those three also committed the same crime as each other, different from the one committed by Linzi, Josh and Kim.’ Simon looked at Charlie properly for the first time since she’d entered the room.

‘Okay, so … hang on. Group 1 – Linzi, Josh and Kim – all committed the same crime as one another, but not together, right?’

‘No. Separately and at different times.’

‘And the other three also? They committed the same crime on different occasions?’

Simon nodded. ‘Want to know the worst thing? None of these people did anything wrong at all. Billy’s idea of a capital offence …’ He finished his sentence non-verbally, with a small shake of his head. He looked utterly defeated, Charlie thought. For a second, she felt afraid.

Pasta was the solution. She fetched Simon’s heaped plate and a fork from the kitchen table and brought it to him in the lounge. ‘Here. You must be starving. I’m assuming you’ve not eaten all day, since you’ve been AWOL on one of your secret missions.’

Charlie had woken this morning at six to find Simon’s half of the bed empty. Normally, his getting up would wake her, so he must have set off at some ridiculous hour when she was still deeply asleep. On the kitchen table, he’d left some stories. Charlie recognised the titles: ‘The Two Sisters’, ‘The Dress’, ‘Loyalty’ … These were stories from the website of Bright Path Ascension Ishaya Lane Baillie (Charlie liked to include Lane’s full title every time she thought of her, in order to enjoy its ridiculousness) that Billy Dead Mates had sent to Sondra Halliday. New Age moral fables: not Charlie’s favourite genre. Simon had summarised each one briefly and dismissively when he’d first mentioned them to her. Since then he’d evidently decided they mattered. On the back of an unpaid gas bill beside the pile of stories on the kitchen table, he’d written, ‘Read these CAREFULLY’. Charlie hadn’t – she’d had to go to work – and was annoyed with herself for having felt guilty all day.

‘So did you go to Poole to see the Asda van biddy?’ she asked Simon.