‘Muriel Pearson? No. I sent Wing to do it for me. Gave him a script, told him to stick to it word for word.’

‘And?’

‘A good result. Muriel Pearson confirmed what I’ve known for a while.’

‘I hope you praised Wing to the skies. From what you’ve said about him, that would make his year.’

‘I went one better and told him what I know: why Billy’s doing what he’s doing. Not for general consumption – yet.’

‘You didn’t!’ No way had he told James Wing before her; no way.

‘I did.’

‘You bastard. You want me to be angry, don’t you?’

‘No.’

‘Well, I’m not.’ Charlie consoled herself with the knowledge that she too was keeping something secret: the plan she’d made with Kim Tribbeck for tomorrow. Perhaps she’d ring James Wing and tell him, make him swear not to tell Simon.

She went to fetch her own dinner. By the time she returned to the lounge, she thought she’d worked something out.

‘The different crimes committed by the two groups of three – they must be connected,’ she said. ‘If they weren’t … I mean, imagine Group 1 have all driven after necking a bottle of gin and then run over and killed a small child. Meanwhile Group 2 are all embezzlers who’ve defrauded the companies they work for. If each member of Group 1 is paired with a member of Group 2, as best friends or family, that’s too unlikely.’ Charlie was frustrated. She knew what she meant but couldn’t express it. ‘It’s too much of a coincidence if Group 1’s crime has nothing to do with Group 2’s. Billy wouldn’t just happen to know three pairs of people in which one has embezzled and the other’s a drink-drive killer. So the only other possibility …’

‘Go on.’ Simon sounded interested.

‘Group 1’s crime must be linked to Group 2’s. Like, imagine the pairs were married couples instead of best friends or grandmother and granddaughter. Married couples with children. Let’s say all three husbands beat up the children, and all three wives turned a blind eye and let it happen because they were scared of their husbands. In that scenario, you’d have three pairs of two but also two groups of three: one from each pair who did the beating, and one who condoned and looked the other way.’

Simon smiled. His mouth was full of pasta, but that was a definite smile. ‘Bang on,’ he said once he’d swallowed the mouthful. ‘And now that you’ve got that far, it ought to take you three seconds to work out the rest.’

One. Two. Three.

‘Um …’

‘All right, three’s a bit ambitious. Five seconds.’

Charlie sighed. ‘Can’t we spend even one second concentrating on the bit I’ve cleverly worked out, instead of berating me for not knowing everything there is to know?’

‘Did you read the three stories?’

‘Not yet.’