Umber followed the coast road out through St Helier's straggling eastern suburbs. The retreating tide had revealed great stretches of grey-brown reef, so extensive that the sea was a mile or more from the shore. The weather was a mix of winter grimness and spring cheer – ambiguous, uncertain, on the cusp of the seasons.

He sighted the first of several martello towers marked on the map as he neared Le Hocq. He pulled in there and waited. When only five minutes remained till Marilyn's noon appointment with Wisby, he drove on.

It was barely another mile to La Rocque. He slowed as he passed its martello tower, scanning the arc of parking spaces facing the harbour. He was looking for a hire car similar to his own. And he saw one almost immediately, his eye drawn to the H-prefixed numberplate. There was a single occupant, staring straight ahead at the harbour, in which assorted craft lay beached at their moorings. The profile was Wisby's.

He pulled in to the left of the car and looked round, meeting Wisby's gaze, in which there was not the merest flinch of surprise, though a surprise it must have been – and a big one.

Umber climbed out, carrying the briefcase with him. He opened the passenger door of the other car and eased himself in beside Wisby, cradling the case in his lap.

'Mr Umber,' Wisby said neutrally, with no hint of fear or hostility. 'We meet again.'

'Not in your game plan, I dare say.'

'No. But I wasn't to know you'd got into bed with Marilyn Hall, was I?'

'She thought you might try to trick her,' Umber replied, refusing to be provoked. 'A chap with your track record must expect that.'

'Well, I should congratulate you, I suppose. You get the Junius after all. And Mrs Hall pays for it. Sorry I left you in the lurch at Eden Holt, by the way. It was nothing personal.'

'Did you really do all this just for a fat pay-off?'

'No. But I've decided to settle for one. You too, I imagine.'

'I'm getting nothing out of this.'

'Really? I can't believe you haven't cut a deal with Mrs Hall. Why else should you be acting as her go-between? What have you gone for? Cash… or kind?'

'Where are the books?'

'Ah. Is that it? A late revival of your historical career. Junius: the truth at last. I might have a minor disappointment for you on that front.'

'I know the fly-leaves are missing, Wisby. I checked with Garrard. Like you should have.'

'I should. You're right. But you said yourself the vellum-bound 1773 edition is unique. Even without the fly-leaves, it proves my case. A case Marilyn Hall can't afford to let me go public with.'

'Exploiting the Hall family's grief is beneath contempt.'

'That's what you think I'm doing, is it?'

'What would you call it?'

'How much do you know about Marilyn Hall, I wonder? Less than me, I suspect. A lot less. I've enquired into her background, you see. I've done my research.' Wisby smiled thinly. 'Like you should have.'

'And what have you learned?'

'Enough to make me worry I may have settled for too modest a sum.'

'Are you going to tell me what you're getting at?'

'No.' Wisby squinted out towards the distant ocean. 'I'll let you find out in your own good time.'

'Where are the books?' snapped Umber, losing patience with the game-playing.

'You can have them when I have the money.'

'How about when you see the money?' Umber flipped up the lid of the briefcase, giving his companion a clear view of the contents. There was a gleam of satisfaction in Wisby's eyes and a greedy little swipe of his tongue along his lower lip. He reached out for the case. But Umber held on. 'The books. Remember?'

Wisby looked at him and grimaced, as if giving up what he had come to trade genuinely pained him. 'They're in the glove compartment. In front of you.'

Umber stretched one hand forward to open the compartment. Its door flopped down. And there were the books, vellum-bound and gilt-edged, held together by a rubber band as he had seen them before. The spines were facing him. He angled his head to read the gold-lettered titles. Not Junius's Letters I and Junius's Letters II, like every other edition he had come across, but simply JUNIUS 1 and JUNIUS 2.

'The money, Mr Umber,' said Wisby. 'If you please.'

Umber surrendered the case and took the books out of the glove compartment. It was strange – surpassingly strange – to lay his hands at long last on the prize Griffin had promised to deliver to him at Avebury twenty-three years previously. He peeled off the rubber band and opened the first volume.

A few jagged scraps close to the binding were all that remained of the fly-leaf. But the title page was untouched. The name of Junius appeared at the top in bold Gothic capitals. Umber's gaze shifted to the bottom. Printed for Henry Sampson Woodfall, MDCCLXXIII. The date was right. And the binding was right. It was Junius's personal copy.

He looked round at Wisby, who was checking his way through the money, fanning each wad of notes and counting roughly as he went. Then he looked back at the Junius, shaking his head: £100,000 was a high price to pay for two mutilated old books. Nor was it by any means the highest price to have been paid for them. They were not worth Jeremy Hall's life. Yet he had lost his life because of them. Volume two fell open in Umber's hands at the last paragraph of Letter LVIII, encouraged to do so, he guessed, by being pressed flat on a photocopier some weeks before. There was the fateful phrase Jeremy had chosen near the end of the letter. 'The subject comes home to us all.' And so it did.

The snapping shut of the briefcase interrupted Umber's thoughts. 'It seems to be all here,' said Wisby, with a flicker of a smile.

'Did you doubt it would be?'

'I doubt everything.'

'Yes. I suppose you would.'

'Why were the fly-leaves removed, do you think?'

'You tell me.'

'It's obvious, isn't it? To break the evidential link with Griffin. Without them they're just another copy of Junius's letters.'

'Not quite.'

'No. But they'd seem so, other than to an expert. And having removed the fly-leaves, where better to lose the books, so to speak, than an antiquarian bookshop? I doubt Garrard's scatterbrained brother bought them. I suspect they were simply slipped onto the shelf. Not by Jeremy, obviously. Perhaps by someone who was trying to keep them from Jeremy. By implication someone Jeremy knew, resident on the island. Someone… close to him.'

'Like you say, Wisby. You doubt everything.' The man's logic was as seductive as it was disturbing. But Umber had no intention of acknowledging as much. 'Are we done?'

Wisby nodded. 'I believe we are.'

A few minutes later, Umber sat in his hire car, watching Wisby drive away. Wisby was heading west, probably making for the Airport. He had every right to be well pleased with his day's work. But Umber's work was far from done. He skip-read his way through Junius's grandiloquent Dedication to the English Nation at the beginning of volume one of the Letters till he had given Wisby the ten-minute start he had agreed to. Then he started the car and headed in the same direction.