Bundled in their woollen coats, Song and the children bustled out the front door and onto the footpath. Wellie and Mac trotted ahead on their navy leads, sporting identical coats in navy and red tartan. They were on their way to dinner, as Song had arranged for the locks to be changed. Apparently, there had been a string of robberies in the area, though Max wondered if it had more to do with Song’s unexpected visitor than any petty thefts.

Kensy and Max walked beside one another in stony silence. They had just had a fight and neither of them was ready to make up yet. In all her excitement, Kensy had told her brother about her watch and the geriatric gymnast across the road, and hadn’t appreciated him laughing in her face and telling her she was imagining things yet again.

The group turned left at the end of the street and were treated to a view of the River Thames on the other side of a busy four-lane road.

‘I see the dogs have taken a shine to you both,’ Song said, in an effort to liven the mood. ‘They are very fussy when it comes to giving their affections. Any love they have for me is only on account of the fact that I feed them.’

‘If the dogs belong to Dame Spencer, why doesn’t she take them with her when she comes to the city?’ Kensy asked.

‘Allergies,’ Song replied with a sigh.

Max’s brow furrowed. ‘But if she’s allergic, why does she have them at all? That doesn’t seem right,’ he said, earning a growl from both terriers.

‘Oh no, not Dame Spencer,’ Song said, shaking his head. ‘Her butler.’

Kensy frowned. ‘Hang on, I’m confused. I thought you were her butler?’

‘At Alexandria, but not here in the city,’ Song said, as if it were the most obvious conclusion.

Kensy glanced at her brother. A silent message passed between them and their fight was forgotten. ‘Song, could you take us to meet her tomorrow?’ the girl asked. ‘We know her office is nearby on the main road.’

‘We want to thank her for letting us stay in her house,’ Max chimed in.

‘Well … Dame Spencer is a very busy woman,’ the butler said hesitantly. He noted the looks of disappointment on the children’s faces and quickly added, ‘But I will see what I can do.’

Literally just around the corner from Ponsonby Terrace, Song and the children walked the short distance to an establishment called The Morpeth Arms, where they would be having dinner. It sat on the corner of another row of Georgian terraces, wrapping its way around into Ponsonby Place. Baskets of red geraniums decorated the frontage along with planter boxes bursting with blooms. It was an impressive display considering it was almost winter. Song pushed open one of the front doors and shepherded the twins and dogs into the pub.

The atmosphere was as warm as the temperature inside, with several tables occupied by locals and business people alike, unwinding at the end of their busy days. A jolly man with a round face and smiling blue eyes gave Song a wave from behind the bar. Wellie and Mac wagged their tails at high speed as a young woman rushed through from a back room.

‘Hello babies,’ she cooed. ‘I’ve missed you two.’ She ruffled their furry heads. ‘Hello Song, hi kids,’ she said, then took the dogs’ leads and promptly disappeared with them.

‘Miss Kensington, Master Maxim, this is my good friend Gary,’ Song said, introducing them to the friendly barman. ‘And that whirlwind of a girl was Stephie – she will look after Wellington and Mackintosh while we have our dinner. They are not allowed upstairs in the restaurant.’

‘Hiya kids,’ the fellow said with a wave. ‘I’ve saved the best spot in the house for you. But before I show you to your table, I’m going to take you on a grand tour of the cells downstairs.’

‘Cells?’ the twins said in unison. Both of them thought Gary must have meant the cellar.

Max spotted a television screen in the corner of the room and a sign underneath that read Can you see our ghost?  He nudged Kensy. ‘I wonder if it’s got anything to do with that.’

Song pulled a face. ‘I am sure that Master Maxim and Miss Kensington would love your special tour, but I am afraid it may give them nightmares – especially if you happen to run into anyone down there.’

Kensy giggled. ‘Max might be scared, but I’ll be fine. I don’t have nightmares.’

‘That’s not true,’ her brother grumbled under his breath.

‘Fantastic!’ Gary exclaimed. ‘Follow me.’

The barman steered the children through to a back room, where they descended a steep, narrow staircase. Song opted to stay behind. Downstairs, the air was cloying and musty, and the twins both felt an immediate drop in temperature.

Kensy’s mouth gaped open as she looked around. ‘There are cells.’

Max peered into one of the tiny spaces. They were only a couple of square metres at most, with a curved brick ceiling. Even he couldn’t stand up inside without having to stoop.

‘They’re so small,’ Kensy observed. ‘It wouldn’t be very comfortable to sleep in there – I mean, your bed would hardly fit.’

‘No beds, I’m afraid. And not just one prisoner. Anything up to fifteen adults would be crammed into that space,’ Gary said sombrely. ‘It was a horrid business.’

Max’s eyes widened. ‘But why were they kept here? I can’t imagine that many people in the pub were so badly behaved they had to be locked up.’

Gary roared with laughter and admitted he’d considered housing some of his rowdier patrons down there on more than one occasion, except that the bars to keep people locked in were missing these days. He explained that there had once been a huge prison further up the road. It was eventually closed in 1890 and now a magnificent museum called the Tate Gallery stands in its stead. But in the old days, it was a much darker place and The Morpeth Arms had served as the officers’ local watering hole.

Gary told them, from a bird’s-eye view, the prison looked like a flower – with six pentagonal buildings around a central hexagon. The plans were rather beautiful, but the reality of the prison was far from it. There were tunnels beneath the gaol and one of them led to the cells under the pub. The officers used it to herd inmates downstairs if there was an overflow from the prison, or they would march them under the roadways and hold prisoners there before they were brought up to be loaded on the convict ships that were bound for Australia. Apparently, the better classes of Londoners weren’t keen to see riffraff on the streets.

A shadow passed across the wall and Max jumped into the air. ‘Did you see that?’ he asked the others.

Kensy spun around, hoping to catch a glimpse.

‘I think you may have just spied one of our friendly ghosts,’ Gary said, grinning. ‘Or it might have been the cat bounding about on the stairs back there – she’s probably been spooked by Wellie and Mac. They are not friends.’

Nonetheless, a shiver ran down Kensy’s spine and she clutched her brother’s arm.

‘I thought you said you weren’t scared,’ Max said. He’d never admit it, but he was quite glad she was holding on to him, even if the shadow did belong to the cat.

‘I’m not,’ the girl said. ‘I’m just cold, that’s all.’

‘Do the tunnels still exist?’ Max asked.

‘I imagine they do, but you’d have to dig through there to find them,’ Gary said. He led the children along the row of cells which came to an abrupt end with a brick wall. ‘This whole area is a labyrinth. They’ve uncovered a few bits and pieces when there’s been building work, but unless a house comes down, they tend to leave things alone. English Heritage has enough to do without looking for more work.’

Max ran his hand over the cool bricks. In one of the cells, he found a name that had been carved into the wall. He wondered who Henry Ball was and what he’d done to end up there. His mind turned to his parents. What if they were somewhere suffering a similar fate? There may have been a couple of hundred years and some thousands of miles between what had happened here and where his parents were in Africa, but the boy couldn’t help thinking about the possible parallels.

The children trekked back upstairs behind Gary, but instead of stopping at the pub level, they continued on up another couple of flights to a beautiful dining room. Decorated in rich red wallpaper with sepia photographs and other artworks, there was a fireplace and side tables adorned with lamps. It reminded Kensy of Dame Spencer’s house in the countryside, although the pieces here showed quite a bit more wear and tear. Apart from a couple sitting on the other side of the room, the restaurant was empty. Gary ushered the children to their table, which was perpendicular to one of three floor-to-ceiling double-hung windows overlooking the river. Instead of individual chairs, there was an elegant button-upholstered double lounge seat on either side of the table.

‘Welcome to the Spying Room,’ Gary announced, and handed each of the children a pair of binoculars.

‘What?’ Kensy screwed up her nose as she shuffled into her seat by the window.

Max sat down and peered outside. ‘Whoa! You can see MI6 right across there, lit up like a Christmas tree.’ He turned to Gary. ‘So, we’re allowed to spy on the spies? Is that why it’s called the Spying Room?’

Gary nodded. ‘Not just allowed – I strongly encourage it. You never know what you might learn by sitting here.’

Song appeared in the doorway. ‘I see you have Miss Kensington and Master Maxim on the hunt already,’ he said with an amused grin.

‘Have you ever seen anything interesting?’ Kensy asked. She tried to get a peek inside the glass-fronted building while Max adjusted the focus on his binoculars.

‘Well, here’s the thing,’ Gary began. ‘In all the years I’ve been managing this establishment, I’ve seen the lights go on and off – same with the computers. I’ve seen people on the balconies, but I’ve never once spotted a human being inside that building.’

The twins put down their binoculars and stared at him.

‘Are you sure?’ Kensy said. She gazed at the building with renewed interest. It reminded her a little of a Mayan temple.

The manager nodded and crossed his heart. ‘Same goes for every other person working here. Anyway, I should let you have a gander at what you’d like for your dinner.’

‘Why don’t you join us?’ Song suggested.

The man protested that he didn’t want to intrude, but the children practically begged him to stay. They were dying to hear more of his stories. Gary finally agreed, and the group placed their orders. Kensy opted for a burger while Max and Gary chose the cod and chips. Song selected a sirloin steak, medium-rare. It seemed like no time before their meals arrived.

‘So, how was your first day at school?’ Song asked.

‘It was good,’ Kensy said, munching on a fistful of fries. ‘We made lots of friends, which is always a bit surprising on your first day, although I’m not sure about a few of them.’

Max frowned at her, wondering what she was getting at. He’d ask her later. ‘Some of the teachers are hilarious,’ he said, and soon had them all in stitches re-enacting Mr Reffell’s impersonation of Lord Nelson.

‘Do you know the lady who owns the newsagency at the end of the street?’ Kensy asked, once they’d exhausted their school stories. ‘She’s awful. I wouldn’t be surprised if she had a giant oven out the back reserved for children.’

‘Ah, that would be Mrs Grigsby,’ Song said with a nod. ‘She is undeniably the meanest woman I know.’

‘Wait till you meet her son, Derek,’ Gary added. ‘He has a diamante earring the size of a pigeon’s egg and more gold chains than the Mayor of London. He’s also partial to wearing his pants halfway down his backside. He got himself a new tattoo recently and, I must say, I laughed out loud when I saw he had the word “genius” on his forearm spelt with a “J”.’

Max collapsed into a fit of giggles. ‘You’re making that up!’

‘I wish I was,’ Gary said, shaking his head.

‘Derek is not what we would consider the sharpest tool in the shed,’ Song agreed. ‘But don’t worry, Mrs Grigsby will leave you alone when she realises you are with me. I take her dumplings whenever I am in London, though she always complains there are never enough. That is because she is very fat.’

‘That’s true. And why would you take her anything?’ Kensy asked, appalled.

‘Confucius says keep your friends close and your enemies closer,’ Song said, waving his steak knife in the air.

Max cocked his head to one side. ‘I thought that was either Machiavelli or Sun Tzu or maybe it was from a movie.’

Song pursed his lips. ‘Hmm, you are much too clever for an eleven-year-old,’ he said with mock displeasure.

‘I am too,’ Kensy told the table. ‘I beat Max in the spelling bee this year.’

‘I am in no doubt of that,’ Song said with a decisive nod. ‘You are twins, and twins are always as smart as one another. Except when one twin is much smarter and better looking.’

Kensy glanced up sharply, ready to take exception, while her brother winked cheekily and said, ‘I know exactly what you mean.’