The earl led them through another series of twists and turns to a part of the castle Merry had never visited before. He finally paused before a dark wooden door.

‘The castle’s muniments room,’ he said. Merry looked blank. ‘It contains important family documents. Going back to the eleventh century,’ he added. ‘When we started building the Black Castle.’

Merry almost felt dizzy as she thought of all those years, rolling by. She noted the we. The old family and the new were still so closely entwined, even after nearly a thousand years. Just like her own family.

The earl opened the door. ‘Please,’ he said, gesturing Merry inside.

Two men were sitting at a large green leather desk surrounded by scrolls and laptops. They got up when the earl entered.

‘Gentlemen, I have something rather extraordinary to show you,’ the earl was saying, putting down Merry’s book on the huge desk. ‘Anthony Parks, Idris Philipps, meet Merry Owen.’

Parks looked to be in his mid-thirties, with brutally short black hair. He had the blazing eyes, wiry body and taut face of a marathon runner, and was dressed head to toe in black: jeans and a tight, long-sleeved thermal top.

‘Good afternoon, Miss Owen,’ he said crisply.

‘Afternoon, Mr Parks,’ she replied.

‘Actually, it’s Professor Parks.’

Merry resisted the urge to scrunch up her face. Pomposity was her pet loathing.

‘Oh, so sorry,’ the earl said. ‘And this is my son, James.’

‘Hello, James,’ said Professor Parks, with a great deal more enthusiasm, reaching out to shake James’s hand.

‘Lord James,’ replied James stiffly.

Merry nearly burst out laughing. She felt some of the tension leave her. James never used his title. He was, she knew, doing it solely to amuse her.

Parks reddened slightly and something in his eyes hardened a fraction, but then he recovered quickly, shaking James’s hand with what looked like an extra-firm grip.

‘And this is Dr Philipps,’ the earl went on.

Merry shook hands, said hello. Dr Philipps had a thatch of unruly dark hair, extravagant eyebrows and smiling eyes. Donning a pair of white cotton gloves and squinting to keep a monocle in place, he bent over the book.

He just stared at the cover for a while, saying nothing, not even seeming to breathe; then, very slowly, he opened the book and turned the pages.

Finally he looked up. ‘Well,’ he said. ‘You know what you’ve got here then, do you?’

‘Not really,’ replied Merry, her heart beginning to beat faster. ‘I mean, I know it’s something special and very old, but that’s about it.’

‘I’d like to show my colleagues, I would, at the Museum of Wales. We’ll have to carry out carbon dating too, if you were to allow me, but my gut feeling,’ he rubbed his large stomach, ‘my gut feeling is that what we are looking at here might be, just might be, mind, one of the lost tales of the Mabinogion!’

Merry heard Professor Parks swear and the earl took a step closer to the book, looked from it to Merry, eyes flickering.

‘The Mabinogion itself, as I’m sure you know,’ Dr Philipps was saying, ‘is a collection of eleven stories taken from medieval Welsh manuscripts from around 1060 to 1200. Some say it’s myth. Others truth. Some tales feature King Arthur.’

Merry nodded. She’d been taught about it at the school in Brecon she’d attended before her accident, before she had begun to be homeschooled.

‘But there are suggestions, references in some manuscripts that other stories exist,’ Dr Philipps continued. ‘They are referred to as the lost tales. And this,’ he concluded, giving Merry a profoundly serious look, ‘is, I hazard, one of them.’

‘Goodness,’ Merry managed to say.

‘Bit of a miracle it survived in such pristine condition. Bit of a miracle you found it after all these years.’

‘Where did you find it?’ asked Professor Parks.

‘In a burial mound,’ replied Merry. ‘On my land.’

‘Whereabouts, exactly?’ asked the earl.

‘In the Black Wood.’

‘Ah, the forest that borders our land.’

‘This was some way from the border,’ replied Merry. She felt a sudden surge of panic. Hoped she was right. It was hard to tell in the forest, dense as it was, and she had taken a meandering path.

‘I am sure this is very precious to you,’ the earl went on smoothly, ‘and I can see you feel very protective of it, but may I just keep it for a few days? I could photocopy it, then have it translated for you.’

‘I could make a start on the translation,’ cut in Dr Philipps. ‘I’m familiar with Middle Welsh.’

Merry hadn’t and wouldn’t forgive the earl for their stallion’s death and the strains it had put on her family. She didn’t want to hand over the book. But she did want it translated. Very much.

‘Forgive me being presumptuous here,’ interjected Professor Parks, ‘but I would counsel you most strongly to allow us to retain the book here at the castle for safe keeping. Rather valuable. Might attract unwanted attention.’

‘Oh, don’t worry,’ Merry replied airily. ‘This part of Wales is incredibly safe. No one even locks their doors around here.’

‘Maybe they should,’ Dr Philipps replied, looking concerned.

Stung into decisiveness by the rebuke, and feeling trapped, Merry stared at him, then turned to the earl.

‘Actually, I’d prefer to keep the book with me. It is mine, after all,’ she added.

She saw a mix of emotions race over the earl’s face: surprise, annoyance . . . He wasn’t used to being denied.

‘Of course,’ he replied with cool civility. ‘That is very much your prerogative.’

‘May I at least take some pictures with my phone?’ Dr Philipps asked.

Merry nodded. ‘OK. That’s fine.’

She watched him carefully turning the pages again. He paused at the same one that had caught her attention: a still, dark pool reflecting clouds scudding overhead; a ray of sunlight arrowing down through the water; a thicket of thorn bushes; a nightingale atop an oak, like a witness to some scene occurring off the page . . . it was beautiful and sinister.

Yet it drew her in . . .

‘I’m dying to know what it says on this page,’ she found herself murmuring.

Dr Philipps met her gaze, his own eyes glowing with a kind of sharp intelligence and fascination. ‘All right, young lady. Give me a little while.’

Mrs Baskerville, the de Courcys’ housekeeper, arrived, struggling under a gigantic tray of teapot and cups. She glanced at Merry in amazement. She was well used to seeing Merry in the castle hanging out with James when the family was out, but not here mingling with the earl and his guests.

When she left, Dr Philipps took a sip of tea, put down his cup, and said, slowly, his eyes on the page: ‘There is a cave where the green turns blue, where the earth beside does shimmer. A veil of water guards it well, of its secrets not a glimmer. There is a hole in the stone of sand at the back in the gushing flow; follow it through to another land and all treasures will you know. Twenty strokes have many tried, turning them to blue, of those venturers many have died, only the strong pass through . . .’

His words echoed around the room. For a while, no one spoke. Merry felt almost dazed, as if she were under some kind of spell. Everyone in the library seemed to feel the same. They all had a distant look in their eyes.

Merry jumped up. ‘Right!’ she said, her voice coming out unnaturally loud. ‘I need to get back.’ She picked up her book, re-swaddled it, and enclosed it safely in the chest, which she slid into the plastic bag.

She seemed to have broken the spell, because everyone started moving and talking at once. James walked out with her and she felt the eyes on her back, and in the air the burn of covetousness.