Kensy’s eyes flickered up from her plate towards Song, who, having delivered their meals, was now standing like a sentry by the doorway.

‘Is he humming?’ she whispered to her brother, who had practically inhaled his breakfast. There wasn’t much left on Kensy’s plate either.

Max suppressed a smile. He recognised it to be a well-known country and western tune – his sister’s least favourite type of music.

‘So,’ Kensy said quietly, ‘as I was saying before about the men in the garden …’ She took up her brother’s drink and gulped it down, having long ago finished her pineapple juice. Her adventures outside had left her absolutely parched.

Max looked at the emptying glass. ‘Why are you whispering? And can you stop drinking my apple juice?’

The girl rolled her eyes and plonked the glass on the table. She didn’t want Song to hear, in case he was in on the terrible business with the bodies too. ‘Never mind. I’ll tell you later.’

Max shrugged and glanced around at the conservatory’s white wicker furniture, potted palms and hanging baskets overflowing with red-and-purple fuchsias. ‘Excuse me, Song, but what does Dame Spencer do exactly?’

‘She is a very important businesswoman,’ Song replied with a smile.

‘Isn’t a dame like a “Sir” but for a woman?’ Kensy asked.

A bell tinged softly and the butler walked over and opened a cupboard in the wall, producing two plates of hot buttered toast with just the lightest smidge of Vegemite on Kensy’s and a lathering of peanut butter for Max. There was hot chocolate too.

‘I wonder how Fitz knows her,’ Kensy said between bites. ‘I didn’t think he knew anyone interesting.’

‘Apart from us, of course,’ Max quipped.

Fitz was their father’s best friend and, according to family folklore, he’d arrived on their doorstep, heartbroken after his fiancée had called off their engagement. Fitz had remained to help out when the babies were born and had never left, which their mother said was a very good thing given there were no grandparents or siblings on her or Ed’s sides of the family. The twins often mused that, for such a lovely guy, who wasn’t half bad-looking either, Fitz had a desperately poor track record with the ladies. He kept house while their parents worked, made sure Kensy and Max did their homework and he cooked most of their meals – including a mean apple crumble, for which he’d won several prizes at village fairs on at least three continents. Fitz was also their teacher when school calendars and timetables didn’t fit into their movements around the world. The children loved their ‘manny’ as much as their own parents and couldn’t imagine life without him, although they were keen for Fitz to find love.

‘Max,’ Kensy said, waving a hand in her brother’s face. ‘Hello …? Earth to Max.’

The boy, who had been deep in thought, looked up at her with a raised eyebrow.

‘Go on,’ she said, raising an eyebrow to match his. ‘Ask Song about, you know …?’

Max shook his head. ‘Not yet.’

‘Why not?’ she argued. ‘You’re so stubborn.’

‘I’m waiting for the right time,’ the boy said, and chomped into his piece of toast.

Frustrated, Kensy kicked her brother’s shin under the table.

‘Ow!’ the boy yelped. He glowered at her from beneath his fringe.

‘Fine, if you won’t then I will,’ Kensy huffed, and turned to the butler. ‘Song, Max heard you say something to Fitz about our parents being missing. What did you mean by that?’

Max cringed inwardly. His sister wasn’t the best at playing it cool.

Song’s serene expression didn’t alter. Kensy may as well have asked for another piece of toast. ‘Miss Kensington, Confucius says that if what one has to say is not better than silence, then one should keep silent. It is not for me to discuss. You should speak with Mr Fitz when he returns.’ He stepped forward and began clearing their plates. ‘Now, is there anything else I can get for you?’

‘What’s that supposed to mean?’ Kensy demanded.

‘Why won’t you tell us?’ Max asked. He didn’t know what he had been expecting from the man, but that wasn’t it. The boy wondered if butlers observed a code of silence or if Song had been specifically instructed to keep quiet. His right leg began to jiggle up and down as it often did when he was anxious.

Kensy pushed away her plate. ‘Come on, Max,’ she said, flinging her serviette onto the table and getting to her feet with such force that the glassware rattled. ‘I don’t know about you, but I’ve had enough of being kept in the dark.’

Max stood up too. ‘You seem like a really nice person, Song. I wish you’d tell us the truth,’ he said. Despite the man’s unwillingness to share what he so obviously knew, Max had a feeling that Song was the kind of guy you wanted on your team. There was a goodness in his dark eyes. ‘Please, Song, they’re our parents. We deserve to know what’s going on.’

Song nodded and smiled at Max kindly. ‘Confucius also says three things cannot be hidden: the sun, the moon and the truth. You will have your answer soon enough, Master Maxim.’

And with those words of wisdom, a feeling of complete dread clawed at the pit of the boy’s very full stomach as he turned to follow his sister.

‘Where are you going now?’ Max asked. He could understand why his sister was cross, but he wished she would learn to control her temper. Song definitely wasn’t going to tell them anything after that outburst.

‘I don’t know,’ Kensy snapped. ‘I just couldn’t stand being in there a minute longer with old Master Confusing. The man speaks in riddles. Why wouldn’t he answer the question?’

Max shrugged. ‘Maybe Fitz told him not to. I can’t believe he’s gone and left us alone in a strange place with no explanation. It’s not like him at all. He could have at least written a note.’

Kensy spun around and looked her brother in the eye. Her mouth felt as if it were stuffed full of cotton wool and her heart was beating madly in her chest. Tears welled in her eyes. ‘Max … do you think it could be true?’ she asked in a wobbly voice.

Max reached out and squeezed his sister’s hand. ‘I don’t know what to believe, Kens. But until we talk to Fitz, there’s no point getting upset. You and I both know how resourceful Mum and Dad are. They save people’s lives all the time. They’re not about to go and get themselves into trouble.’

Kensy hugged her brother fiercely. It didn’t happen very often, especially now that they were eleven. As embarrassing as it would be if someone saw them, right at the moment it made them both feel a little better.

‘You’re right,’ she whispered. ‘Why are you always the calm and sensible one?’ She fought back another wave of tears and let go of him. ‘Mum and Dad are fine. They probably just missed a flight or two, that’s all.’ Her eyes lifted to the portraits around the vestibule and she wrinkled her nose at one particularly stern-looking crone. ‘Do you think she sucked a bag of lemons before she sat for that?’

Max followed her gaze and grinned. ‘They’re all pretty stiff, if you ask me. Although that guy has a friendly face,’ he said, pointing to a portrait of a man in a military uniform. ‘He reminds me of someone …’

Kensy agreed but couldn’t work out who he looked like either. ‘Let’s find out what else is in this palace?’ she said with a glint in her eye. ‘We don’t know when Fitz will be back, so I think we should start at the top and work our way down and I’ll tell you allllll about what I heard in the garden. There might be cold-blooded criminals in our midst.’

Max stifled a smile. Anyone who knew Kensington Grey was well acquainted with the girl’s fanciful theories. ‘An axe-murdering psychopath, perhaps?’

‘You joke now, but you’ll see that this time I might just be right,’ Kensy harrumphed.

The twins bounded up the main staircase, nudging one another as they raced to the top. Max sprinted two steps at a time and was matched by his sister, who was determined to beat him. They reached the landing and collapsed onto the bare boards, puffing and panting and nearly losing their breakfast.

‘I won!’ Max declared breathlessly. He stood up and dusted himself off.

‘Oh, you did not.’ Kensy rolled away and jumped to her feet. ‘Right, time to see what’s hidden away up here.’

The pair walked along the corridor, poking their heads through each and every doorway. As they explored, Kensy told her brother about the vegetable patch and the lady with the squirrel and the conversation she had overheard in the walled garden.

‘Should we call the police?’ she asked earnestly, once she’d finished. ‘Or what about MI5 – or is it 6? Aren’t they the really cool British spies?’

Max wasn’t convinced, but tried to temper his sister’s haste tactfully. ‘Why don’t we tell Fitz first?’ he suggested. ‘He’ll know what to do.’

Kensy nodded. It wasn’t the most exciting option, but she reasoned that the murderers might try to do away with them too if they discovered the twins had dobbed them in to the authorities.

They continued on with Max recounting his morning, including his discovery of The Caesar Shift and the encrypted message inside it. Kensy nodded absently and yawned, all the while secretly chuffed that her story was way more exciting.

‘Do you think she owns a bank or some diamond mines?’ Kensy asked.

‘Who – Dame Spencer?’ Max said. He wondered if Kensy had been listening to him at all – she was clearly thinking about other things. ‘I suppose she could, but you know some people make their fortunes from really ordinary things. Imagine being the person who invented toothbrushes or sink plugs.’

‘Maybe she’s one of those rich aristocrats who has inherited their fortune,’ Kensy mused. ‘I guess we’ll find out eventually. That is, if we’re not held here as prisoners for life.’

Disappointingly, all the doorways had led to bedrooms. Kensy felt as if she would scream if she saw another canopied four-poster bed or antique side table. After fifteen dead ends, she gave up and slumped onto a burgundy velvet chaise longue at the end of a long corridor.

‘Who would’ve thought that someplace so big could be so boring?’ she moaned, pulling a stray leaf from her hair.

‘Mmmm,’ Max replied. He, on the other hand, seemed fascinated by the decor. He was busily running his hands along the papered wall.

Kensy was about to ask what he was up to when a small porcelain dog on the cabinet beside her chair caught her eye. ‘Hello there,’ she said, and reached out to pick it up, almost dropping the delicate thing, when she was startled by a whirring sound. Kensy turned it over, but there was nothing out of the ordinary. ‘Max, can you hear this?’ she asked, giving it a shake.

‘Be careful,’ Max scolded, when his sister tossed the figurine his way. ‘This thing is probably worth more than Mum and Dad make in a year.’

Kensy curled her feet up on the cushioned seat. ‘Go ahead and break it then. You never know, we might get someone’s attention and possibly even some answers.’

Max examined the ceramic creature. He moved it slowly to the left, then to the right, which prompted the same whirring noise as before. His forehead creased with concentration.

‘What’s the big deal then?’ Kensy said impatiently.

‘It’s a camera,’ Max whispered, staring into the porcelain pup’s eyes.

Kensy looked at him dubiously. ‘And you give me grief about making up wild stories?’

The boy opened the cabinet door and deposited the creature inside.

‘Why are you whispering, anyway?’ Kensy asked. ‘Do you think it has a microphone?’

Max shrugged and returned to the wall he had been inspecting.

‘What are you looking at now?’ Kensy groaned. She glanced around the hallway and wondered if there was anything else spying on them, but there was so much junk it was impossible to tell. Kensy stood up and was alarmed to find her sneakers had left muddy marks on the velvet chair. Hastily, she covered the evidence with a cushion before her brother could scold her for it, then peered over his shoulder. For the life of her, she couldn’t see what had piqued his interest.

‘See that there?’ Max said, running his finger along an invisible ruler. ‘That line?’

Kensy squinted at the wall. All she could see were birds and strawberries. ‘What line?’ she grumbled. ‘This is boring, Max. Can we go downstairs now? There must be a cellar and maybe a secret tunnel or something – anything would be more interesting than this.’

‘Just give me a minute.’ Max moved on to the cedar table positioned in front of the wall, his fingers skimming the underside of its smooth marble top until they finally found what he’d been looking for all along. ‘Hey Kensy,’ he said, lifting the latch. ‘Watch this.’

‘What now, M–?’ Kensy’s eyes widened as a section of the wall slid back to reveal an alcove with a spiral staircase leading upwards. ‘Whoa. I bet it’s the tower at the back of the house. I saw it when I was outside.’

Max grinned. ‘You might be able to pick a lock, sis, but that line in the wall there was a dead giveaway. I knew this was a secret entrance to somewhere,’ he gloated. He swiftly located the mechanism to close the panel, then turned to ask his sister if she was coming.

But Kensy didn’t need an invitation. She was already gone.