Friday wasn’t nervous until they landed in Oslo and discovered that the airline had managed to lose her bag. She wasn’t sure how. It was a small plane. There were only about thirty passengers. But the man at the baggage-claim desk was adamant there was nothing he could do – except get them to fill out a form listing everything inside the suitcase. There wasn’t much to list. Her spare brown cardigan, two pairs of jeans, five t-shirts, some underwear and eleven books. The baggage controller assured her the bag would be forwarded to her as soon as they found it. Although he did seem more than a little disbelieving when he saw that Friday had filled in her forwarding address as ‘The Royal Palace, Oslo’.

Friday was intimidated to be going to a palace. It was daunting when they were met by the royal state car. The driver’s uniform had epaulettes, which were both intimidating and silly. But the driver carried it off with aloofness, so it erred on the side of intimidating.

From what Friday could see out of the car window, Oslo was beautiful. It literally looked like a city from a fairytale, which made sense, because so many fairytales originated in Scandinavia. All the buildings looked like storybook illustrations come to life. As a result, everything felt ever so slightly fictional. Like a little mermaid, or a matchstick girl or a handsome prince might appear at any moment.

The car drove up the main street, through the heart of Oslo’s city centre, then straight into the gravel driveway of the royal palace. As they swept around the front of the building, Friday and Melanie got a good look at Ingrid’s home. It was more modern than the type of palaces you see in fairytales – an elegant mustard and white building surrounded by beautiful parkland.

‘Ingrid has a nice house,’ observed Melanie as they glided past wandering tourists, towards the main turning circle. This was not an understatement to her. Melanie knew so many billionaires who had equally nice, if not nicer, houses. But not being members of royal families, these regular every-day billionaires were allowed to keep theirs discreetly tucked away behind thick hedges and tall walls.

‘It must take forever to vacuum,’ said Friday. When she had lived at home, she’d always been the one to do the cleaning. Her parents never touched the vacuum cleaner, except for the one time her father needed a helix to demonstrate a principle of physics and he’d dismantled the Dyson on the kitchen table and taken it to work.

‘Of course,’ said Melanie. ‘That’s how the nobility share their wealth. By having such impossible-to-maintain things that require an army of staff to deal with them. It helps keep the unemployment rate down. It’s their social obligation.’

Friday thought about this idea. She had an enormous mind, but she had not considered ostentatious extravagance in quite this light before.

The car drove past the front of the building and turned right, into a laneway down the side.

‘They’re taking us round to the tradesmen’s entrance,’ said Melanie. ‘I’m sure it’s for our own safety. To keep us away from prying eyes.’

‘Have you visited a royal palace before?’ asked Friday.

‘Yes,’ said Melanie.

Friday was surprised. It must have shown on her face.

‘When I was in preschool with the Princess of Qatar,’ explained Melanie. ‘She had a lovely dollhouse, with stables that were big enough to hold real horses.’

The car had barely stopped moving when a footman in royal livery stepped forward and opened the door.

Friday got out. The air was crisp. It was sunny, but this was autumn in Norway, so as soon as you stepped out of the sun it was cold. She glanced at the footman. He was staring in the general direction of the sky, as though he’d just seen a really fascinating cloud. She assumed this was an etiquette thing – that he had been taught not to look directly at guests. It felt weird.

A young woman, about their own age, stepped forward. She didn’t look Norwegian. Her skin was darker and her hair black, which was surprising enough. There were a lot of blondes in Norway. But it took Friday’s brain a moment to compute the fact that this pretty girl only had one arm.

‘Hello, my name is Saba,’ said the girl. ‘I am Princess Ingrid’s lady-in-waiting. She has asked me to make you welcome until she can arrive from the Galapagos Islands.’

‘What happened to your arm?’ asked Friday.

‘Friday!’ exclaimed Melanie. ‘Where are your manners?!’

‘I’m sorry,’ said Friday. ‘I’m so sorry. I’m not good at manners. Or social niceties. I just can’t fathom how someone so young and pretty could be missing an arm.’

‘Friday!’ wailed Melanie. ‘There can be no happy story explaining it. There is no excuse for you asking such a thing on first meeting a person. Especially a person who has only been polite to you.’

‘Oh gosh, I’m so sorry,’ said Friday. ‘Please forgive me. In my defence I recently spent eleven months in prison. I always had terrible social skills, but being locked in a room on my own for twenty-two hours a day has only made them worse.’

‘It’s all right,’ said Saba as she led them into the building. ‘I have not had an arm for many years now. I am quite used to it, myself.’

‘You shouldn’t let her off the hook so easily,’ said Melanie. ‘You’ll only encourage her eccentric ways.’

‘Do not fear,’ said Saba. ‘Her royal highness, Princess Ingrid, fully briefed me in preparation for your arrival. She explained to me that your friend is borderline rude and uncomfortably honest. I was expecting it.’

‘This is what I need,’ said Friday, turning to Melanie. ‘People to be briefed on my personality before I arrive.’

‘Or – you could try harder to behave yourself,’ said Melanie.

‘I do try,’ said Friday.

‘I know,’ said Melanie, relenting slightly.

‘Does that mean I’m allowed to ask follow-up questions?’ asked Friday.

‘No,’ said Melanie firmly.

‘I don’t mind,’ said Saba. ‘I am a refugee from Eritrea. I lost my arm when a shell hit my house.’

‘I did not expect to meet a refugee from Eritrea in the Norwegian royal palace,’ said Friday.

‘No,’ said Saba. ‘Which is, in a way, why I am here. The people of Norway are good people who want to do the right thing. When Eritrean refugees fled their homes, Norway generously offered asylum. But Norwegian culture is very different to Eritrean culture, which caused some problems. The princess hiring me to act as her lady-in-waiting was an important symbolic gesture – encouraging Norwegians to be generous hosts to refugees.’

‘Ingrid is lovely, isn’t she,’ said Melanie. ‘Binky is such a lucky boy.’

‘He is nice too,’ agreed Saba. ‘And he is your brother?’

‘Yes,’ said Melanie. ‘I have three more brothers. I can introduce you to them some time.’

‘Gosh,’ said Saba.

‘Don’t worry,’ said Melanie. ‘They aren’t all as dim as Binky.’

‘They’re not?’ asked Friday.

‘No,’ said Melanie. ‘Two of them are a great deal dimmer. They’ve gone into international finance. But Peter is the smart one of the family. He drives a bus at Disneyland.’

‘What glamorous lifestyles,’ admired Saba.

She showed them through a series of narrow corridors around the back of the palace.

‘Princess Ingrid’s apartment is at the rear of the building, overlooking the fishpond,’ explained Saba. They had been walking through corridors lined with tapestries, paintings and antique ceramics all strategically placed for maximum interior design effect. Now they had arrived at a yellow door that looked like the front door of an apartment. There was a letterbox on the wall outside, a peep hole in the middle of the door and the number 2 painted above it.

‘Does it say “2” because Ingrid is next-in-line to the throne?’ asked Friday.

‘No, all the apartments in the palace are numbered,’ explained Saba. ‘The king’s private secretary has apartment number 1. It is in the other wing of the building, closer to the king’s office.’

Saba unlocked the door. When Friday and Melanie stepped inside, it was as if they were stepping into a regular inner-city apartment. The ostentatious European knick-knacks were nowhere to be seen. This looked like the apartment of a student. A very well-to-do student, but a young person nonetheless. There was a well-appointed kitchenette. A big comfortable couch. A widescreen TV. Walls lined with books, a great deal of which were not terribly serious novels. As well as movie posters and photographs of friends and family.

‘Look, there’s Binky,’ said Melanie.

There was a photograph on the wall of Binky in his Norwegian army uniform standing next to Ingrid. They both looked awkward. He was a lot taller than her. He looked like he wanted to put his arm around her shoulders but wasn’t sure if he was allowed to.

‘This is your room,’ said Saba, leading them to a door off the living area. Inside was a room not unlike their old dorm room at Highcrest. There were two single beds, a chest of drawers, a big wardrobe and a window with a lovely view over the gardens. This was a little unnerving because there were tourists walking past, just a few metres away.

‘I will leave you to settle in,’ said Saba.

‘Thank you,’ said Melanie.

‘I’m sorry I was rude,’ said Friday.

‘That’s okay,’ said Saba.

‘No, it’s not,’ said Melanie. ‘You need to be firmer with her. She’s like a naughty dog. If you give her a treat when she behaves badly you will reinforce her bad behaviour.’

‘I must go,’ said Saba. Although she still didn’t move.

Friday looked at her. She had seen that look in the eye before. It didn’t matter if you were a one-armed Eritrean refugee lady-in-waiting or a seventh grader worried about a lost science assignment – it was the anxiety of someone who knew they were about to get in trouble.

‘Is there some way we can help you?’ asked Friday.

Saba hesitated. Eventually she said, ‘Her royal highness, the princess, tells me that you are a . . . detective?’

‘Well . . .’ said Friday. ‘I was.’

‘Who are you kidding?’ said Melanie. ‘You were born a detective. You’ve always been a detective. You always will be a detective. It’s just sometimes you get moody or hormonal and kid yourself you won’t be.’

‘You’re a bit moody yourself, today,’ said Friday.

‘It’s palaces,’ said Melanie. ‘They bring out my inner princess.’

‘I have a slight problem,’ confessed Saba.

‘How slight?’ asked Friday.

‘As you know, her highness, Princess Ingrid, is due back tomorrow,’ said Saba.

‘Yes,’ said Friday.

‘I may have – accidentally – lost the most precious stone in all of Norway,’ confessed Saba.

‘The Haakon Stone?’ asked Friday.

‘You know it?’ asked Saba.

‘We went to school with Ingrid for a while,’ said Friday. ‘She wore it around her neck every day. We didn’t realise how significant it was because it just looks like a pebble.’

‘Yes! That’s the problem,’ said Saba. ‘I didn’t realise either! Or I would have put it in a safe. Or at least hidden it from thieves in the pea packet in the freezer. But I just left it on the dresser where she put it.’

‘So what happened?’ asked Melanie. ‘How did you lose it?’

‘Did a bird fly in and snatch it to use as part of its digestive processes?’ asked Friday. ‘I’ve solved crimes with similar solutions in the past.’

‘No,’ said Saba. ‘Sir Eirik’s assistant informed me that he would be coming down to inspect the apartment. The king wanted to get Ingrid a birthday present, and Sir Eirik needed to check it would fit on her wall.’

‘So Sir Eirik stole it?’ said Melanie.

‘Goodness, no,’ said Saba. ‘But Sir Eirik is very particular. All the staff knows this. He will not tolerate sloppiness.’

‘No wonder he doesn’t like Binky,’ said Melanie.

‘The apartment is Ingrid’s personal space,’ said Saba. ‘She doesn’t mind a little mess. She likes to be comfortable. But I knew Sir Eirik would not see it that way. I knew I had to get the apartment immaculate, and quickly.’

‘But . . .’ prompted Friday.

‘It is not easy to clean with one arm,’ said Saba. ‘Not a whole apartment in less than half an hour. So I rang the housekeeping department and asked if there were any cleaners who could come and help me. They sent two women down. And they did a fantastic job. They swept all the junk off the counter tops, tables and surfaces. Wiped and polished everything in the kitchen and bathrooms. Vacuumed the carpet. They were in and out in twenty minutes and the apartment looked beautiful. Everything was shiny. Sir Eirik didn’t say a word. He just came in, looked at the walls and left. I didn’t get in trouble.’

‘Well done, you,’ said Melanie. ‘It’s an important management skill to know when you need to ask for help.’

‘But two days later . . .’ continued Saba. ‘Her highness, Princess Ingrid, rings. She says she will be home for her birthday. Could I please have her blue dress pressed, her satin shoes cleaned and the Haakon Stone necklace ready to wear.’ Tears started to well in Saba’s eyes. Melanie handed her a tissue.

‘What was the problem?’ asked Friday.

‘I didn’t know what this Haakon Stone necklace was,’ said Saba. ‘Her highness says, “Oh, you know, the one that looks like an ordinary pebble? I left it on my dresser.” And I remember it. I thought it was just a rock. She just left it there with all the post-it notes and muesli-bar wrappers and half-used hand-cream tubes. I just thought it was another piece of junk. So I say, “The rock necklace is important?” And her highness says, “Oh yes, it is the most valuable stone in all of Norway. I must wear it for my twenty-first birthday ball. It is expected of me.” So I say, “Okay.” I hang up. And then I am very, very afraid. It must have been thrown away with all the mess. I do not want to be thrown out of Norway for losing the most valuable necklace in the country.’

‘Goodness no,’ agreed Melanie. ‘That would be hard to live down. And, really, Ingrid is to blame. She should have the necklace labelled so people know to be appropriately frightened of its significance.’

‘She probably thinks that its anonymity keeps it safe,’ said Friday.

‘But in this instance, it’s a little too much anonymity,’ said Melanie.

‘I went through all the palace rubbish bins,’ said Saba. ‘It took me all night, but I couldn’t find it. I’m worried that it has already gone to the rubbish dump. I will have to tell Sir Eirik so he can arrange to have the dump searched.’

‘Don’t worry,’ said Friday. ‘You won’t have to tell Sir Eirik.’

‘I won’t?’ said Saba.

‘No, because the stone was not thrown away,’ said Friday. ‘At least, not in the rubbish.’

‘I don’t believe the cleaners stole it,’ said Saba.

‘No, of course not,’ said Friday.

‘So it was Sir Eirik?!’ said Melanie. ‘He’s the thief!’

‘No, that didn’t happen either,’ said Friday.

‘That’s a shame,’ said Melanie. ‘I’ve never met him, but I don’t like him already.’

‘Then what did happen?’ asked Saba.

‘Were the cleaners native Norwegians?’ Friday asked Saba.

‘No,’ said Saba. ‘One was from the Philippines and the other from Bangladesh.’

‘Cleaning is a job commonly held by new immigrants, because you don’t need language skills,’ said Friday. ‘If they were recent immigrants to Norway, they would be unlikely to know about the Haakon Stone and the significance of a rock with a hole in it.’

‘Then who did take it?’ asked Melanie.

‘No one,’ said Friday. ‘You’re assuming someone either stole it because they thought it was valuable, or threw it away because it was rubbish. There is a third option.’

‘Yes,’ said Saba.

‘What if the person who found it did something else entirely?’ said Friday. ‘What if they thought that the Haakon Stone was a stone? Just an ordinary stone. After all, it does look just like a stone. And what would you do if you were standing in this room with a stone in your hand? Think about it . . . You’re meant to be cleaning. The room is being aired.’

‘I don’t know,’ said Melanie. ‘I’ve never given a lot of thought to my actions as they relate to stones.’

‘You’d put it with all the other stones,’ said Friday. She walked over to the window and pointed outside. ‘It is about the size and shape as the pebbles on the gravel driveway.’

Saba gasped. ‘They threw it out the window onto the driveway?!’ she exclaimed. She rushed to the window and looked out. ‘There must be a million stones out here. We’ll never find it!’

‘I don’t know whether there would be a million,’ said Friday. ‘A million is a lot more than the human brain can conceptualise. But there would certainly be several hundred thousand.’

‘Friday,’ said Melanie. ‘I don’t think you’re being as helpful and reassuring as you might be. Saba appears to be having a panic attack.’

Saba was sitting on the bed, breathing very rapidly.

‘It’s all right,’ said Friday. ‘I’m sure we’ll find it. It won’t be too hard once we narrow down the search parameters.’

Melanie sat down next to Saba and gave her a reassuring hug. ‘Have faith,’ said Melanie. ‘This is just the sort of conundrum Friday loves sorting out.’

Friday went back to the window and climbed out through it.

‘Is she running away?’ asked Saba.

‘No, gathering evidence,’ explained Melanie. They went to the window to watch.

Friday was sitting on the driveway, rubbing her foot.

‘I fell and twisted my ankle,’ explained Friday.

‘Of course you did,’ said Melanie. ‘I would expect nothing less.’

Fortunately, Friday was used to twisting her ankle, so it didn’t take her long to recover and get back to work.

‘We need to ask ourselves, how far would they have thrown it,’ said Friday. ‘Far enough to get out the window, but they wouldn’t throw it with all their might, in case they hit a passing tourist in the head.’

A group of young school children were approaching along one of the park’s paths. It would have been dangerous to be throwing rocks nearby.

‘So I think we can narrow it down to further than two metres from the window,’ said Friday. ‘But less than eight metres. That’s not too much area to cover.’

‘It’s still tens of thousands of stones,’ said Melanie.

‘Then we need a large search party,’ said Friday. ‘Saba, how good is your Norwegian?’

‘Pretty good,’ said Saba. ‘I take evening classes three times a week.’

‘Okay,’ said Friday. ‘Could you please ask those school children if they’d like to help? You could tell them you need to find a precious stone to rescue a princess from being locked in a dungeon by her angry father. Given the way children are indoctrinated through fairytales with morality stories fixated on royalty and precious objects, I would be very surprised if they were not excited to help.’

Soon Friday, Melanie, Saba and sixty school children were on their hands and knees, scouring the gravel of the driveway for a stone with a hole in it. It took eight minutes before Bjørn, a seven-year-old with a very runny nose, found it. The other children were terribly disappointed and wanted Friday to throw it again so they could keep looking. Melanie made it up to them by buying them all ice blocks from a nearby van.

Saba was delighted to have the mystery solved. She took great care in putting the Haakon Stone away safely.

‘You should use a hot glue gun to stick some diamonds to it,’ said Friday. ‘Ingrid might be a bit less lackadaisical with it, that way.’

When they had settled into their room, Friday used Ingrid’s phone to call Bernie back and see how things were going in Bilbao.

‘You were right,’ said Uncle Bernie as soon as he picked up.

‘Oh good,’ said Friday. ‘So you arrested the conservator?’

‘Not exactly,’ said Uncle Bernie.

‘Surely you either arrest someone or you don’t arrest someone,’ said Friday. ‘There are no shades of grey.’

‘I confronted Dr Lopez,’ said Uncle Bernie. ‘She laughed in my face and confessed it all.’

‘That sounds good,’ said Friday.

‘Then she made a run for it,’ said Uncle Bernie.

‘She outran you?’ asked Friday. ‘Don’t you have lots of security guards on staff? She managed to outrun all of you?’

‘It sounds silly when you put it that way,’ said Uncle Bernie. ‘But the thing is, most security guards are men. And men are instinctively hesitant to crash-tackle women. Especially well-dressed, pretty women. And extra especially well-dressed, pretty women in wheelchairs.’

‘Oh,’ said Friday, catching on to what he meant. ‘She out-rolled you.’ Friday could visualise the awkwardness of the situation.

‘Also, there was just the sheer logistics of it – how do you crash-tackle a wheelchair?’ said Uncle Bernie. ‘I know I’ve never had to do it before. It’s not something they taught us when I went through the police academy. I used to play professional ice hockey. I know how to slam into an enormous man wearing a helmet, carrying a stick and with blades strapped to his feet, but it’s hard to know how best to slam into a metal wheelchair travelling at forty kilometres an hour.’

‘Surely she wasn’t going that fast?’ said Friday.

‘She wasn’t until she got to the ramps,’ said Uncle Bernie. ‘The Bilbao Guggenheim prides itself on its accessibility to the differently abled community. That means there are lots of ramps. Once she hit those, she was moving like a Formula One driver.’

‘So no one could stop her?’ asked Friday.

‘Oh, I stopped her,’ said Uncle Bernie. ‘I leapt over three balustrades, short-cutting the ramps and got to the lobby just after her. Once we were on the flat of the forecourt out the front of the museum, I started to narrow the gap.’

‘Well done, Uncle Bernie,’ said Friday. ‘I didn’t know your cardio-vascular system had it in it.’

‘As Dr Lopez slowed to turn around the giant sculpture of a puppy made out of flowers, I launched myself at her, smashing the wheelchair over, and knocked her to the ground,’ said Uncle Bernie.

‘So you did catch her?’ said Friday.

‘No,’ said Uncle Bernie. ‘A retired police sergeant visiting from Devon was so horrified to see a grown man crash-tackle a disabled woman, that he punched me really hard in the face and I was knocked unconscious. That’s when she legged it. We found her car abandoned at the port. She must have swapped to a boat. She could be anywhere.’

‘Wow,’ said Friday. ‘You lost the painting and you got a head injury. You’ve had a really bad day.’

‘Oh, this is more than one day’s worth of pain,’ said Uncle Bernie. ‘There are already videos of the whole thing all over social media. I’ve had disabled-rights groups calling me to complain all afternoon.’

‘Were any more paintings missing?’ asked Friday.

‘Yes,’ said Uncle Bernie. ‘We’ve found eight so far. She was really good, so they’re hard to spot. Luckily, she used cheap frames from Ikea, so we can work out which are forgeries by looking at the label.’

‘Have you been able to recover the originals?’ asked Friday.

‘No,’ said Bernie. ‘There’s nothing at her flat. But every Tuesday for the last eight weeks, she booked a courier to pick up a package and take it to a shipping office in Barcelona.’

‘That’s not good,’ said Friday. ‘That’s one of the busiest ports in the world. It’s the perfect place to smuggle things out of Europe.’

‘I know,’ said Bernie. ‘I’m trying to get hold of someone in customs to allow us to investigate. I’m going to have to travel there myself. I don’t suppose you could get here in time to come with me?’

‘I can’t leave now,’ said Friday. ‘But could you do me a favour?’

‘Sure,’ said Bernie. ‘It’s not like I’m busy or anything.’

‘Oh good,’ said Friday, not picking up on the sarcasm. ‘Could you run a check on Dr Klaus Finsberg?’

‘What’s he done?’ asked Bernie.

‘Probably nothing,’ said Friday. ‘But he works with Binky at Svalbard. I just want to make sure Binky is all right out there.’

‘I’ll run him through the database,’ said Bernie.

‘Thank you,’ said Friday. ‘And let me know what you find in Barcelona.’