Friday rang Uncle Bernie while they were waiting at the airport for a flight out of Bardufoss. There wasn’t really anything else to do. The kiosk didn’t have a terribly good selection of reading material if you weren’t interested in Norwegian celebrities or hunting equipment. It took a while for Bernie to pick up.

‘Hello,’ said Bernie.

‘It’s me,’ said Friday. ‘Your niece, Friday.’

‘Hello, Friday,’ said Bernie. ‘I do recognise your voice.’

‘Really?’ said Friday. ‘I sometimes find it hard to recognise voices. It seems rude not to specifically identify yourself.’

‘It doesn’t feel strange to specifically identify yourself?’ asked Uncle Bernie.

‘Most human interactions feel strange to me,’ said Friday. ‘It’s hard to distinguish.’

‘When are you going to get here?’ asked Uncle Bernie. ‘Ian is upset that you didn’t come with us.’

‘Did he say that?’ asked Friday.

‘Well, not in words,’ conceded Uncle Bernie. ‘But he is glowering and brooding a lot.’

‘He always glowers and broods a lot,’ said Friday.

‘Yes, but he’s doing it even more than usual,’ said Uncle Bernie.

‘We’ll be there soon,’ said Friday. ‘We’ve just got to go to Ingrid’s birthday party. It’s a big deal. She’s turning twenty-one. She threatened to block our passage through the border if we don’t go.’

‘Do you want me to put Ian on the phone?’ asked Uncle Bernie. ‘It won’t take me long to fetch him. I’d rather you told him than me. I don’t want to see the hurt in his eyes.’

‘No, Ian will be fine,’ said Friday. ‘It’s just another week or so . . .’ Friday realised that Bernie had put the phone down. ‘Bernie, Bernie, I rang to talk to you, not Ian!’

‘Hello.’

It was Ian.

Friday’s pulse accelerated and she went all hot and cold. How could hearing his voice do this to her? The human endocrine system was an extraordinary thing.

‘Hello,’ said Friday.

‘Oh, it’s you,’ said Ian. From his carefully neutral tone, Friday couldn’t gauge his attitude. To be fair, even if he had a non-neutral tone, Friday was terrible at gauging things like that, so she’d probably be just as clueless.

‘We’ve been delayed here in Norway,’ said Friday.

‘Trouble with the reindeer?’ asked Ian.

‘Reindeer?’ said Friday. ‘Is that a Santa Claus reference?’

‘Yes, because you’re in the Arctic Circle,’ said Ian.

‘Oh,’ said Friday. ‘And it’s impossible to believe that somewhere so snowy and remote, and associated with Christmas mythology, could require my presence as a detective?’

‘Well deduced,’ said Ian. ‘You get a gold star for figuring out a joke.’

‘I’m not staying to solve a crime,’ said Friday. ‘I’m staying for Ingrid’s birthday party.’

‘And you have a great passion for playing pass-the-parcel?’ asked Ian.

‘I don’t think they play pass-the-parcel at royal balls,’ said Friday.

‘Sarcasm,’ said Ian. ‘I was being sarcastic.’

‘Oh,’ said Friday. Ian’s voice was beginning to make her have sinking feelings in her stomach. ‘Ingrid has sent you an invitation.’

‘It must have got lost in the post,’ said Ian.

‘Well, you have just moved,’ said Friday. ‘That is entirely possible.’

‘I’ve got responsibilities here in Bilbao,’ said Ian. ‘So do you.’

‘I’ll be there in a week,’ said Friday.

‘I hope that the Guggenheim hasn’t been entirely stripped of exhibits by then,’ said Ian.

‘What do you mean?’ asked Friday.

‘Talk to Bernie,’ said Ian. ‘He’ll explain it. I’ve got to go to school.’

The phone clattered as if it had been put down on a table.

‘Ian?’ said Friday. ‘Ian?’

She heard the phone get picked up again.

‘Ian?’ asked Friday.

‘No, it’s me, your uncle, Bernie Barnes,’ said Uncle Bernie.

‘You see, I appreciate that,’ said Friday. ‘You identify yourself clearly. There’s no confusion.’

‘I’m rolling my eyes now, just so you know,’ said Uncle Bernie.

‘So has there been a theft at the Guggenheim?’ asked Friday. ‘Why haven’t I seen that in the papers?’

‘We’ve managed to hush it up so far,’ said Uncle Bernie. ‘We’ve got an exhibition here at the moment – it’s of Kandinsky paintings. Do you know Kandinsky?’

‘Early twentieth-century Russian expressionist painter, known for his bright use of colour,’ said Friday.

‘That’s the one,’ said Bernie. ‘It’s been super popular. Really boosted visitor numbers to have his paintings here. They’re a big deal. Even an idiot like me can see that they’re beautiful pictures.’

‘He is more cheerful than a lot of expressionists,’ agreed Friday.

‘He’s even bigger in Russia,’ said Bernie. ‘It took a lot of persuasion and assurances to get big galleries like The Met and Lenbachhaus to lend so many pictures. The Bilbao Guggenheim already had state-of-the-art security throughout the building. It’s not like the Uffizi. This is a modern building, constructed specifically to house valuable art. And all that got ramped up for this exhibition with more guards and greater security measures – no bags, not even handbags in the gallery, no coats. Everyone must pass through whole body scanners. It couldn’t have been more secure.’

‘But?’ said Friday. ‘I can sense a “but” coming.’

‘But last night, after the visitors had left, the cleaning crew came in to do the gallery,’ said Uncle Bernie. ‘You know what gallery types are like with dust . . . and acid levels in dust . . . and moisture levels and how that affects the acid in dust. They take it super seriously. The gallery has to be cleaned meticulously every night.’

‘So what happened last night?’ asked Friday.

‘One of the cleaners tripped over the cord of her vacuum cleaner,’ said Uncle Bernie. ‘And her sleeve, ever so slightly, brushed the surface of one of the paintings.’

‘Well, that’s unfortunate but it’s hardly a crime,’ said Friday.

‘That’s not the problem,’ said Uncle Bernie. ‘The problem is, when she straightened up, she had paint on her sleeve. The painting was wet.’

‘What?’ said Friday.

‘It was completely fresh paint,’ said Uncle Bernie. ‘The whole thing. It was a forgery.’

‘And no one noticed?’ asked Friday.

‘It was a really good forgery,’ said Uncle Bernie. ‘Besides, it hadn’t been there long if it was still wet. An oil painting takes about twenty-four hours to dry.’

‘Longer, surely, if it was a Kandinsky,’ said Friday. ‘He used really thick paint. Those expressionists all do. Like Van Gogh. They couldn’t express all that repressed emotion with a regular amount of pigment. Was it an earlier work? Or from his later period?’

‘His Blue Rider period,’ said Uncle Bernie.

‘Yeah, that’s when he started to slather it on,’ said Friday. ‘Was it a large painting?’

‘Not really,’ said Uncle Bernie. ‘About forty centimetres by forty centimetres.’

‘That makes sense. Artists usually start out smaller so they don’t have to spend as much on paint,’ said Friday. ‘Of course, some kept costs down by using egg-based tempera, but Kandinsky used oils.’

‘Friday, I need you here,’ said Uncle Bernie. ‘Something weird is going on. If it’s a big burly robber barging in and snatching things off the walls, I’m your man. I can deal with that sort of crime. But this weird stuff is beyond me. I need your help to try and figure it out.’

‘I’m not a miracle worker,’ said Friday.

‘Yes, you are!’ said Uncle Bernie. ‘I need you to do that thing where you crawl along the floor sniffing things, then stand up and patronise everyone for five minutes before revealing who did it.’

‘Uncle Bernie,’ said Friday. ‘This crime is so weird, I don’t have to do any of that. It’s obvious who did it.’

‘It is?’ asked Uncle Bernie. ‘Who? It’s not Ian, is it? Please tell me it’s not Ian.’

‘No, of course it’s not Ian,’ said Friday. ‘Unless he’s injured himself and had to start using a wheelchair.’

‘What are you talking about?’ asked Bernie.

‘The thief is a wheelchair-using art conservator,’ said Friday. ‘You have one on staff, I take it?’

‘Yes, we do, Dr Nora Lopez,’ marvelled Uncle Bernie. ‘But how on earth can you possibly know all that?’

‘Precisely because I’m not there in Bilbao enjoying the sun-drenched climate, getting to personally know the museum staff and experiencing the emotion of the work on the walls,’ said Friday. ‘You told me the facts and, unclouded by any emotion, I can deduce what happened from those. If I was there, I might easily be distracted by the common misdirects of miscreants.’

‘Okay, you’re going to have to take me through this step-by-step,’ said Uncle Bernie. Friday could hear the rustle of him getting his notepad and pen. ‘Start from the beginning. I’ll never understand otherwise. I’ll jot it all down.’

‘First of all, if the painting is forty centimetres square,’ said Friday, ‘there is no way you could conceal that inside a piece of clothing. And if no bags are allowed in the gallery, the thief had to smuggle it in some other way. It can’t have been the cleaning crew, because it had been twenty-four hours since the crew came through. The painting would have been dry by then.’

‘Okay, that makes sense,’ said Bernie.

‘But . . .’ continued Friday, ‘. . . the seat of the average wheelchair is approximately forty centimetres by forty centimetres. You could slide a framed canvas under the seat and smuggle a forgery in that way. Once inside, you simply swap it with the real painting, tucking that back under the wheelchair. Of course, to do that the thief would have to stand up, so that’s how we know they don’t really need the wheelchair.’

‘So someone pretending to need a wheelchair,’ said Uncle Bernie.

‘And you know it had to be someone on staff,’ said Friday, ‘because everyone is searched on their way in and out of the building. The thief got around that by painting the forgery inside the museum.’

‘Inside!’ exclaimed Bernie. ‘This is bad.’ Friday could hear him scribbling on his notepad.

‘You can’t forge a convincing masterpiece in five minutes, so you couldn’t do it in a toilet cubicle or a stairwell,’ said Friday. ‘It would take hours and require a lot of equipment. Apart from anything else, oil paint smells. You couldn’t go unnoticed unless you were in the conservation workshop, where all that equipment would be available and in use as a matter of course. And, being an art conservator – someone professionally trained to clean and touch up paintings – she would have all the skills.’

‘Surely someone would notice,’ said Uncle Bernie.

‘Not necessarily,’ said Friday. ‘The Bilbao Guggenheim is a modern art gallery. The exhibits wouldn’t need that much conservation. I doubt people are blundering into the paintings all the time. There are probably only a couple of people in the department. Perhaps they work flexible hours and Tuesday is the one day of the week when our thief has the conservation workshop to themselves.’

‘I’d better go and check this out,’ said Uncle Bernie.

‘And check all the other paintings in the gallery that are under forty centimetres square too,’ said Friday.

‘Why?’ asked Uncle Bernie.

‘If your thief is that good at forgery,’ said Friday, ‘who knows how many times they’ve already got away with it?’

‘Oh no, this is bad,’ said Uncle Bernie. ‘This is really, really bad.’

‘Flight 264 to Oslo is now boarding,’ said an announcer over the airport’s PA system.

‘That’s my flight,’ said Friday. ‘Good luck.’

‘I’ll need it,’ said Uncle Bernie.