Grant had his notebook out. ‘And what’s your address, Mr Eadie?’ He started to take down Eadie’s details.

‘He’s not the Quizmaster,’ Siobhan stated.

‘The who?’ Eadie asked, his voice wavering.

‘Never mind,’ Siobhan said, dragging Grant away by the arm. They went back to the car, and Siobhan started typing an e-mail:

Ready for Hellbank clue.

She sent it, then sat back.

‘Now what?’ Grant asked. Siobhan shrugged. But then the laptop announced there was a new message. She clicked to read it.

Ready to give up? That’s a surer thing.

Grant let out a hiss of breath. ‘Is this a clue or a taunt?’

‘Maybe both.’ Another message came through:

Hellbank by six tonight.

Siobhan nodded. ‘Both,’ she repeated.

‘Six? He’s only giving us eight hours.’

‘No time to waste then. What’s a surer thing?’

‘Not a clue.’

She looked at him. ‘You don’t think it’s a clue?’

He forced a smile. ‘That’s not what I meant. Let’s take another look at it.’ Siobhan put the message back up on the screen. ‘You know what it looks like?’

‘What?’

‘A crossword clue. I mean, it’s not quite grammatical, is it? It almost makes sense, but doesn’t.’

Siobhan nodded. ‘Like it’s a bit strained?’

‘If it was a crossword clue …’ Grant pursed his lips. A little vertical crease appeared between his eyebrows as he concentrated. ‘If it was a clue, then “give up” could mean “yield”, as in yielding meaning. Do you see?’

He fumbled in his pocket, brought out his notebook and pen. ‘I need to see it written down,’ he explained, copying out the clue. ‘It’s a classic crossword construction: part of it tells you what you have to do, part is the meaning you’ll have if you do it.’

‘Keep going. You might start making sense soon.’

He smiled again, but kept his eyes on the words in front of him. ‘Let’s say it’s an anagram. “Ready to give up … that’s a surer”. If you give up – meaning render or use – the letters in “that’s a surer”, you’ll get a word or words meaning a “thing”.’

‘What sort of thing?’ Siobhan could feel a headache coming on.

‘That’s what we have to find out.’

‘If it’s an anagram.’

‘If it’s an anagram,’ Grant conceded.

‘And what’s any of it got to do with Hellbank, whatever Hellbank is?’

‘I don’t know.’

‘If it is an anagram, isn’t that too easy?’

‘Only if you know how crosswords work. Otherwise you’d read it literally, and it wouldn’t mean anything at all.’

‘Well, you’ve just explained it and it still sounds like gobbledygook to me.’

‘Then aren’t you lucky I’m here? Come on.’ He tore off a fresh sheet of paper and handed it to her. ‘See if you can unscramble “that’s a surer”.’