‘Jesus,’ muttered Oliver, clearly asking himself the same question. ‘You think your uncle buried it already?’

  ‘No,’ said Anna. ‘I’d have noticed.’

  ‘But if he took the trouble to cover his—’

  ‘You can’t just dig up a tilled field without leaving traces. Certainly not in the middle of the night.’

  ‘Then?’

  ‘How about this?’ she said, while running her torch across the floor, which at least relieved her of one concern, for there was no sign that Uncle Dun had ever made it through his hole. ‘He has it all lying on the ground next to him, planning to bury it next. Only that’s when Gregory Scott comes across him.’

  ‘So he killed him out of greed,’ said Oliver. ‘Bang goes his claim of self defence.’ He shook his head, struggling to take it in. ‘I don’t get it, though. What even is this place? Why go to all the trouble and risk of hijacking John’s baggage train only to wall it up again?’

  ‘I don’t suppose they meant it to be forever,’ said Anna. ‘But obviously I got it wrong earlier. They didn’t weed out the Lynn coins as they took them out to spend. They did it all upfront. I mean look at this stuff. What does it have in common?’

  ‘Apart from being priceless, you mean?’

  ‘Yes. Apart from that.’

  ‘Come on, Anna,’ he sighed. ‘Just tell me.’

  ‘It’s that it’s identifiable. The Lynn pennies we already know about. But look at these brooches and buckles. Animals and birds, flowers and geometric patterns. Trust me, anyone who’d seen them before and who had even a half-decent eye would have recognised them at once.’

  ‘And the silverware? The goblets?’

  ‘Stamped with a royal crest, I’ll bet. King John and his army were only a day’s ride away. For all anyone here knew, he might have got wind of what they’d done and been already on his way. So they’d have needed to get rid of the evidence fast. They might even have prepared this place ahead of time. It wasn’t as though they’d have been needing this stuff anytime soon. They’d have had cartloads of coins and bullion and other anonymous loot that they could safely add to their general stores. But not this. This would see them hanged. They didn’t have time to cut it up or melt it down either, so they had to separate it out and wall it up until it was safe again.’

  ‘Which it was within days,’ pointed out Oliver. ‘After John died.’

  ‘Yes, but only to be succeeded by his son. A son who’d loved him dearly. Better safe than sorry, right? Wait until the dust had fully settled. Henry was a Plantagenet, after all, and only a boy. Some ambitious cousin was sure to knock him off in a month or two. But he lived fifty more years, during which time Temple Bruer would have filled with idealistic young knights who’d have felt great loyalty to their new king, and who’d have been horrified to learn that their order had been party to his father’s murder.’

  ‘That’s an awful lot of daisies for a single chain,’ said Oliver. ‘And if you’re right, where are the crown jewels? The sceptres? The Sword of Mercy?’

  Anna didn’t answer, struck by a different curiosity. She reached across to raise Oliver’s camera so that its lamp lit up the facing wall, and yes, there was indeed a mural on it. She’d missed it before, partly because it was half hidden behind the two silver platters, but also because its colours had faded over the years, and because it was naturally dark and shadowy anyway, being of a night-time scene, as attested by the crescent moon in its top right corner. But it was easy enough to make out, now that Oliver’s lamplight was upon it. Its main subjects were two men wearing hooded capes over chain-mail coifs and coats, seated together upon a chestnut warhorse with a white blaze. They were depicted in three-quarter profile, as if headed off over Anna’s left shoulder, while a line of other mounted knights trailed along behind, riding escort to a baggage train.

  ‘My god,’ muttered Oliver. ‘They painted their own confession.’

  ‘Their own homage, more like,’ said Anna. ‘They’d all have been for the gallows anyway had this place ever been found. So why not celebrate it where they could?’

  ‘A whole damned baggage train. You’d think those two up front could afford a horse each.’

  ‘It’s a symbol,’ she told him. Two men on a single horse had been depicted on Templar seal stones, pottery and everything else. All kinds of ingenious explanations had been offered for this, including that it had been to honour the poverty of their two founders, or to represent their dual roles as warriors and monks, or their refusal to leave fallen comrades behind on the battlefield. But no one knew for sure.

  The two knights in the motif were typically depicted in profile, charging the enemy with a lance and a shield apiece. Yet its use here couldn’t be an accident. No. It was meant as a tribute to these two particular men. What was more, Anna knew who they were. The man sitting behind had to be Aymeric de St Maur, head of the Knights Templar in England. She was confident of that, even though she didn’t recognise him, because she did recognise the man in front, the evident leader of this extraordinary expedition, for his long thin face, his aristocratic nose and chevron moustache were virtually identical to those on his tomb effigy in London’s Temple Church.

  It was William Marshal, St Maur’s closest friend and the hero of her thesis.

  SEVENTY-EIGHT

  Traffic was rush hour heavy as Elias headed back south out of Lincoln towards Temple Bruer, but he had so much on his mind that for once he was content to let the cars around him set his pace. He tuned his radio to an oldies station then tried to assemble the various facts of Dunstan Warne’s murder into a coherent picture. But he invariably had a piece or two left over that he couldn’t get to fit. He gave a defeated sigh as he approached Navenby, then turned his radio down to call Quinn yet once more. ‘You must be sick of me by now,’ he said.

  ‘I’m still hiding it okay, though, aren’t I?’

  ‘You are, you are,’ he assured her. ‘But this Warne business is driving me nuts. Mind if I think out loud?’

  ‘Go for it.’

  ‘Okay,’ he said. ‘Let’s start with this. Maybe Priya was lying about what time Scott left. Say he went at five-thirty instead of a quarter past six, and he saw Warne digging in his field on his way home.’

  ‘It would have been dark still.’

  ‘I know. I know. But perhaps he had a lamp or something. Allow me a bit of rope here. Anyway, he hurries over to investigate and he finds Warne planting his silver pennies. Maybe he has a bagful of other goodies too, and the greed is too much for him. He kills Warne, buries him, grabs his loot and legs it. So my first question is this: what happened to Warne’s spade? He must have had one to dig his hole, right? Yet we didn’t find it with his body, even though it would have been easy enough to bury it with him. So Scott must have taken it, yes? But then why not dump it in the salt marsh with his own? Or hang it up in his shed, in place of his own? Who’d have noticed? Come to that, why toss his own spade out in the salt marsh at all? He’d lived there fifteen years. He must have known it could be spotted at low tide. Surely better to wrap it in a bunch of bin bags and dump it in a lake somewhere. And that’s before we get to the intruder lights. Because didn’t you tell me they were difficult to see in the morning, as it was already getting light?’

  ‘Yes. So?’

  ‘You’ll know that coast better than me. Say you wanted to dump a spade out in the salt marsh, but it’s starting to get light. What are your chances of wading out thirty metres or so, dumping it and making it back again, all without being spotted? By someone out for a jog, say, or walking their dog before setting off for work?’

  ‘Oh,’ said Quinn. ‘I see what you mean. Those seawalls get busy early. And you can see for miles once it starts getting light.’

  ‘Exactly. It would have been a crazy risk, even for someone in a panic. Surely you’d wait for night instead, when you could be certain of not being seen. Except the intruder lights would have come on if he’d done that, which they didn’t, not until the storm, at least, which was hardly the kind of weather you’d want to wade out onto the salt marsh in, and which could easily have triggered them all by itself.’

  ‘So Priya was telling the truth. Like I said.’

  ‘That’s how it looks. Except how then did Scott’s spade get out there? And what happened to Warne’s?’ He’d arrived outside Temple Bruer while they’d been talking. There was no sign of Merchant’s BMW, but he pulled to a stop anyway, switched off his engine. ‘You could just about construct a scenario whereby someone else borrowed Scott’s spade to go treasure hunting. They surprised Warne and used it to kill him and then dumped it. But who? I doubt Penny Scott has the strength for a blow like that. And who else? One of those old couples from the hotel? The environmentalist with the broken ankle? I mean come on. So maybe the spade wasn’t used to murder Warne, but was thrown out there to make Scott look guilty. Now I can see the wife doing that, especially if she’d found out about her hubby’s affair. A sweet bit of revenge while getting to keep the house and all the money. Except if the intruder lights clear the husband, they surely clear her too.’

  ‘It’s a puzzler,’ agreed Quinn.

  ‘A puzzler? Is that the best you’ve got?’

  ‘Like you’re doing so much better.’

  ‘True enough,’ he sighed. ‘But keep thinking. Call me if you come up with anything.’

  He grabbed his torch and went to explore. The tower was dark and empty and quiet, save for someone in a neighbouring house pumping out some early Taylor Swift. He went upstairs to make sure, though without much expectation. Dunstan Warne had photographed fields, not buildings. He stood at a window and stared out towards Wellingore. Lights twinkled from a house or two, but that was it. Yet Warne had found a cache of ancient treasure somewhere in that darkness, Elias was sure of it, and all his instincts were telling him that Anna and Merchant were out there right now, searching for the spot.

  SEVENTY-NINE

  Anna waited for Oliver to film his fill of the treasure chamber, then they headed back the way they’d come. Their duty to report this place was clearer now than ever, yet there was still at least one more section to explore, and curiosity so trumped responsibility that they waded across the flooded hall to it without exchanging so much as a word.

  A short passage opened up into what had clearly once been a chapel, with a high vaulted ceiling and rows of pillars carved with demons and angels, and stone benches either side of a central aisle oriented to face a large dais a bare few inches above the water. A long white marble table stood at the front of this dais, making it easy to imagine some Templar notable celebrating mass or calling a meeting to order. But it was the wall behind it that stunned Anna, covered as it was by a mural of such bright fresh colours that it was instantly obvious how the towels she’d found bagged up in the back of Uncle Dun’s van had got so wet and filthy.

  Oliver gave a coughing kind of grunt, as though someone had punched him lightly in the gut. He waded past her, splashing up the aisle, turning his camera this way and that as he went. Anna hurried after him. A flight of steps took them up onto the dais. Oliver stood back a little way, the better to pan across the whole wall, but she went straight up to it. Though no art historian, even she could tell at a glance that it was a fresco, a technique popular in ancient Egypt and Greece before falling out of fashion, only to be revived in medieval Italy and then spread across Europe by returning crusader knights.

  The vividness of colour alone would have suggested as much, painted on while the plaster was still wet, allowing the pigments to soak right in. Equally revealing was the greyness of the backdrop sky, for blue had been the one pigment that wet plaster hadn’t absorbed well, and so had tended to fade over the decades. But the biggest tell by far was that fresco artists had only had eight hours or so before the plaster set too hard, at which point they’d had to stop for the day, returning the following morning to cut away the unused areas and start afresh.

  The seams between these different panels – giornatas as they were known, from the Italian for a day’s work – tended to crack over the centuries. And as the artist would typically concentrate on completing a single element of the larger painting each day, this had the incidental effect of putting a kind of aura or halo around the key figures, exactly as had happened here with the mural’s central subject, a boy in splendid purple robes with a gold circlet on his head, seated upon a throne so much too large for him that his legs were left dangling several inches above the floor.

  Who else but Henry III, and at his coronation too? That had taken place inside Gloucester Cathedral, of course, but he was shown here in the great outdoors, the artist taking full advantage of their licence to fill the background with the towns and villages of this green and pleasant land, as well as with cheering crowds of nobles and commoners alike. A work of historic importance, then, yet turned into a masterpiece by the boy’s expression, overwhelmed by the magnificence of the occasion, yet determined to make his late father proud.

  A man was standing a little behind and to the side of the throne, his head respectfully bowed as if not wanting to be noticed. The artist had portrayed him as a vigorous if grizzled middle-aged warrior, his hand resting loosely upon the pommel of his sheathed sword. William Marshal again, serving as regent to the boy king, and thus England’s de facto ruler. He too had a telling expression on his face: not of triumph at his ascension but rather of solemn awareness of his responsibility, leading a bankrupt country still at war with itself.

  It was no great surprise to find Henry honoured here, for kings were always liable to drop in unannounced on tours of their realm, but it was a puzzle to see Marshal so prominently feted. He’d become a Knight Templar on his deathbed, true, inducted by Aymeric de St Maur himself, but he hadn’t yet been one at the time of Henry’s coronation. Though in a sense he had been, for he’d pledged himself to the order many decades before, while in the holy land on crusade – a crusade he’d only ever gone on because of the vow he’d made to Young King Henry as he’d lain dying.

  So many vows. So much sudden death. ‘I think I have the answer to your question,’ murmured Anna, turning around to Oliver.

  ‘What question?’ he asked.

  ‘About why St Maur still had John killed even after pulling off his heist.’

  Oliver turned his camera on her, its lamp so bright that it made her squint. ‘And?’

  ‘It was never about the treasure. It was always about killing John. And St Maur wasn’t even the man behind it. He was just another member of the cast. An important one, yes, but still. The baggage train was his pay-off.’

  ‘Then who was behind it?’

  Anna nodded at the fresco, at the man standing beside the throne. ‘Him,’ she said. ‘William Marshal.’

  Oliver gazed sceptically at her. ‘History’s greatest knight? England’s chivalric hero? A common assassin?’

  ‘Hardly a common one. And it’s not that unthinkable, is it? We know for a fact that he’d been involved in at least one royal murder before.’

  ‘You mean Young King Henry’s?’

  ‘No, actually. I’m talking about Arthur of Brittany.’ But Oliver looked so blank that she knew she’d have to elaborate. ‘Arthur was the son of Geoffrey, another of John’s older brothers to die young. He probably had the strongest claim to succeed Richard Lionheart to the throne. It was just that John moved faster. Arthur didn’t give up, though. He won the backing of the French and went to war, only he got unlucky and was captured. John held him in Rouen while he and his closest advisors agonised over what to do, because killing a king was such a no-no, even for John. Yet they killed him anyway.’

  ‘And Marshal was part of it?’

  ‘He never spoke of it, but yes. We can place him there from other sources.’

  ‘So much for his famous gallantry.’

  ‘There was a lot at stake, to be fair.’

  ‘And that makes it okay, does it? You can kill a king if the prize is big enough?’

  ‘I’m not just talking money and power. There was a war going on. Killing Arthur would have looked like a way to end it at a stroke, and bring peace to…’ But then she fell silent.

  ‘Bring peace to…?’ prompted Oliver.

  ‘Nothing,’ she said. But Oliver kept his camera on her face, and she felt compelled to continue. ‘It’s just, there’s a bit of a pattern with Marshal. I’ve been aware of it forever, everyone has. It’s part of what made him such a legend. But I’ve only just noticed it, if you get the difference, even though it happened again and again and again.’

  ‘Go on.’

  ‘Okay. It’s that every time Marshal served a king, that king died. What’s more, their death proved to be Marshal’s stepping stone to a bigger and better job under their successor – even though those kings and their successors had pretty much all been literally at war with one another.’

  Oliver shook his head. ‘I don’t get it.’

  ‘Maybe it would be easiest if I went through them. Arthur of Brittany you already know about. And Young King Henry we discussed yesterday. Remember how I said the Old King rewarded Marshal handsomely after his return from the crusades? Well, he invited him to join his court too. He became very good friends with the new heir presumptive Richard Lionheart while he was there. But then Richard rebelled against his father too, only more successfully than his brother had done. The two sides met outside Le Mans. Richard won. The Old King had to flee the field. Marshal famously dropped back to buy him time to escape, while Richard himself led the pursuit. He and Marshal actually met right there on the battlefield. The two great champions of English knighthood. Marshal used to boast afterwards that he was the only person ever to best Richard in single combat. He could have killed him, he claimed, but he drove his lance through his horse instead. Richard used to seethe at the story, but he never denied it. Yet we only have their word for it that it happened that way. What if there was no fight? What if they talked instead? Marshal was a pragmatist. He knew the Old King was lost, and that prolonging the war would only cause needless suffering. There was an obvious deal to be struck.’