‘I don’t even know where the main lobby is,’ said Friday, looking about at the dimly lit corridors that spread out in three different directions from where they were standing.

  Ian stared at her in disbelief for a moment. ‘It’s the big room in the middle of the building with a glass pyramid on top,’ he said. ‘It’s hard to miss. How can you be so smart but be confused by the layout of a building?’

  ‘If we were outside, that would be different,’ said Friday. ‘I could navigate by the stars.’

  Ian took out his mobile. ‘You need to get a phone.’

  ‘So I can use Google Maps?’ said Friday. ‘Any hacker can use that data to track your location, you know.’

  ‘They could,’ agreed Ian. ‘But you can also download a compass app.’ Ian tapped an icon on the screen and a compass appeared. ‘Now you can navigate.’

  ‘That is pretty cool,’ said Friday, genuinely impressed. ‘But I could also use my actual compass.’ She pulled a compass out of her pocket and held it on her palm. It looked just like Ian’s app.

  Ian rolled his eyes. ‘Come on. We need to go south.’ He grabbed her hand again and started striding confidently into the bowels of the building. A few minutes, several staircases and many twists and turns later, they turned into the room where the Mona Lisa was on display.

  Friday was breathless from trying to keep pace with Ian. When she stepped into the room, she was delighted to see her uncle.

  ‘Bernie!’ she cried.

  ‘You’re here!’ said Uncle Bernie.

  Friday hurried over to hug him, then thought better of it, which made Bernie self-conscious. Then, after the awkward hesitation, Friday suddenly felt like crying. Being a deductive genius, she realised this was probably because she’d been through so much upheaval in the past ten days – she was really glad to see her loveable, kind-hearted uncle. Friday lunged forward to hug him, which Bernie didn’t quite anticipate, so it ended up that she sort of hugged his waist while Bernie patted her shoulders.

  Ian rolled his eyes. ‘You two are as painfully awkward as each other.’

  ‘You’re looking much better than last time I saw you,’ Bernie told Friday. ‘Less blue.’

  ‘What were you doing in Germany?’ asked Friday.

  ‘Finding an expert, or “connoisseur” as they’re called in the art world,’ said Bernie.

  Ian chuckled. ‘I thought a connoisseur was an ice cream.’

  ‘I’d love an ice cream,’ said Bernie wistfully. He turned to look at a group of men standing over near the Mona Lisa. They were all dressed in suits. They exuded importance. ‘But we’ve got to deal with this first.’

  ‘Are you going to introduce us?’ asked Friday.

  ‘Probably better if I don’t,’ said Uncle Bernie. ‘The tall guy on the left in the sharp suit is the director of the gallery. He’s a bit upset already. Anything could set him off into a full-blown tantrum at this point. You’d better just observe.’

  ‘Observe what?’ asked Friday.

  ‘Our connoisseur,’ said Uncle Bernie. ‘Professor Abernathy is going to examine the painting.’

  ‘The Professor Bertram Abernathy?’ asked Friday. ‘From Leipzig University and former director of the Zentralinstitut für Kunstgeschichte?’

  ‘The one and only,’ said Bernie.

  ‘I’ve got his book,’ said Friday. She opened her shoulder bag and pulled out the massive textbook she’d read on the plane. ‘It’s very thorough. Very, very thorough. Even I found it dry, and I like reading theoretical physics dissertations.’

  Friday peered around Uncle Bernie. A very small, very elderly man was standing next to the balustrade in front of the Mona Lisa. A large, old-fashioned leather briefcase sat at his feet. But Professor Abernathy wasn’t looking at the painting. He was looking at his shoes, which admittedly were quite interesting because one was black while the other was brown. Professor Abernathy seemed to be lost in deep thought. Although he may have simply been trying to politely ignore the director of the Louvre, who seemed to be working himself into a full-blown rage.

  ‘I forbid it, I forbid it!’ declared the director, holding his finger in the air and waggling it to emphasise his point. As if he wanted God up in heaven to see what was going on.

  ‘But we just want to take a look,’ said another man. This man was very well dressed and well groomed. A bit too well, perhaps. He looked like he dyed his hair and had an extensive skincare regime.

  ‘That’s the minister for the arts and cultural affairs,’ explained Bernie. ‘I asked him to come and reason with the director. I thought the director was being difficult with me because I’m a foreigner.’

  ‘And you look like a thug,’ said Friday.

  ‘Yes, that too,’ agreed Bernie, glancing down at his large waistline. Uncle Bernie had played ice hockey for the Riga Raiders in his youth. He was very large and very stocky. Somehow, despite now being married to an ardent vegetarian, he still managed to maintain a very high calorie, high cholesterol diet. ‘These arts types are tremendously prejudiced against the burly.’

  ‘You should be ashamed.’ The director was still denouncing the minister. ‘You are a traitor to your country!’

  ‘It turns out,’ whispered Uncle Bernie, ‘that the director is just as rude to his fellow countrymen.’

  ‘You are vandals,’ said the director. ‘All of you are seeking to vandalise this great national treasure.’

  Friday made a snorting sound. The director’s head snapped round.

  ‘Who is this little girl who sounds like a pig?’ demanded the director. ‘You bring in crowds of children now to insult me.’

  ‘Not crowds,’ said Uncle Bernie. ‘Just two. They’re investigative consultants from Interpol. They’re just here to observe.’

  ‘And to make animal noises,’ said the director. ‘So now we have an oaf and a pig.’

  ‘You’re the one who’s being oafish,’ said Ian, protectively taking a half step towards Friday.

  ‘And now I am to be insulted inside my own gallery?’ demanded the director.

  ‘It’s not your gallery,’ said Friday. ‘It belongs to the people of France.’

  ‘I’m insulted again,’ declared the director. ‘The pig child explains my job to me.’

  Ian took Friday’s hand and squeezed it, a little too hard. Like he wanted to use that hand to punch the director, but squeezing Friday’s hand was the next best thing.

  ‘Professor Abernathy just wants to take a look at the painting,’ said the minister calmly, as if he were speaking to a deranged lunatic, not a professional museum director.

  ‘He can look. He can look all day long!’ said the director. ‘Let the man look. I’m not stopping him.’

  ‘But to observe the brush strokes and colour properly he needs to see the painting without the bulletproof glass,’ said Uncle Bernie, in the tone of a man who had said this same thing several times before.

  ‘No, no, no!’ said the director. ‘The case maintains perfect temperature and humidity to preserve the masterpiece. I refuse to allow it to be exposed to pollution.’

  ‘But the Mona Lisa was exposed to open air for four hundred years before it was put behind glass in 1956,’ said Friday. ‘A half hour while the professor looks at it won’t do it any harm.’

  ‘Oh, the pig girl is an expert in paint preservation also?’ said the director sarcastically. ‘This girl – she is most incredible!’

  ‘She is, actually,’ said Ian.

  ‘Jean Pierre, please,’ said the minister.

  ‘I refuse,’ said the director. ‘I hold the only key to this case. No-one can open it without my permission. I do not give that permission.’

  ‘We can get a court order,’ said Uncle Bernie.

  ‘You could just punch him and take it,’ mumbled Ian.

  ‘You think you could get a court order?’ said the director. ‘I would like to see you try! The judiciary in the country respects the arts. They will protect the Mona Lisa from being violated.’

  ‘Achem,’ said Professor Abernathy, speaking for the first time. He spoke slowly and with a quavering voice distinctive of the elderly. ‘Perhaps you should have had this discussion before flying me here.’

  ‘I’m sorry, sir,’ said Uncle Bernie. ‘I knew the director didn’t want the painting to be physically tested. I didn’t realise he had an objection to it being viewed as well.’

  ‘I will return to my home in Leipzig,’ said the professor, picking up his bag and handing it to his assistant. ‘You can contact me if you resolve this.’

  ‘No, please,’ said the minister. ‘You’re here now. Can you please inspect the painting through the glass. See if there is anything noteworthy.’

  The professor shook his head. ‘This is not ideal. Not ideal at all.’

  ‘No, but the glass is clean. You brought your equipment with you. You have magnifying lenses you can hold against the glass to observe the brushstroke in detail,’ said the minister. ‘You will be able to form some opinion.’

  The professor made some soft clucking noises. Friday suspected he just wanted to go home. All the elderly people she had ever known always wanted to go home once it got dark outside. He didn’t look like he’d be an exception. But there were so many people in the room. Aside from Friday, Ian, Bernie, the director and the minister, there were also several security guards, ministerial assistants and gallery staff standing around watching the professor. He obviously felt he had to do something, so he approached the painting.

  ‘If you would be so kind?’ the professor said. A security guard was blocking the end of the balustrade. The professor waved his hand, indicating that he would like to pass through to the other side and get closer. The security guard looked to the director for instruction. The director looked mutinous, but even he, a deeply unreasonable man, could not think of a reasonable or unreasonable reason not to let this frail old man get closer to the thick bullet-proof glass.

  The professor shuffled around and stood directly in front of the Mona Lisa. There was just the width of the bench between him and the glass protecting the painting. His assistant came forward and put the professor’s equipment bag on the benchtop.

  The director audibly hissed at this imposition.

  The assistant opened the bag and took out several tools before handing the professor a magnifying lens.

  ‘Thank you,’ said the professor politely. The assistant bobbed his head, almost like a bow, then stepped back. The professor put the large end of the magnifying aid to his eye, the small one to the glass and slowly moved across the surface as he methodically looked at every tiny detail. Friday watched, fascinated. So did everyone else in the room. It was so quiet and the room was set up like a shrine. It felt like they were observing a religious ritual. And, like a religious ritual, the whole process went on for a mesmerically long time.

  Uncle Bernie started to fidget. Even Ian was shifting from foot to foot, waiting for the professor to make some sort of proclamation. Professor Abernathy had, so far, methodically worked his way across about half the painting with the eyepiece. His pronouncement was not likely to come any time soon. Friday was fascinated by his meticulous process. She opened her copy of the professor’s book and started jotting notes on the title page. The professor kept up his inspection for nearly half an hour. No-one said anything. They just watched the old man at work.

  Eventually, Professor Abernathy stepped back, looked at the painting from that position, then shook his head.

  ‘No,’ said the professor.

  ‘It’s not the Mona Lisa?!’ said Uncle Bernie.

  ‘Outrageous slander!’ accused the director.

  Professor Abernathy winced. ‘No, not no, no, that’s not what I mean,’ said the professor. ‘Well . . . maybe. But in this case I mean, no, I can’t give an opinion.’

  ‘What?’ said Uncle Bernie.

  ‘Yes!’ exclaimed the director in triumph.

  ‘I can’t be sure,’ said the professor. ‘Not without a closer inspection. Even then . . .’ he trailed off, tilting his head to one side and pouting. ‘Da Vinci was so experimental that any idiosyncratic techniques could be evidence of forgery or simply that he was trying new things. It would take years of minute analysis to form an opinion. Even then, it would just be that – an opinion.’

  ‘But you must have a hunch,’ said Ian. ‘A sense about it. If you’ve studied all da Vinci’s work for years, you must have a feeling whether or not this is one of them.’

  The professor took off his glasses. He cleaned the thick lenses with a handkerchief while shaking his head and smiling. ‘I have been called here to give my expert opinion and I have done that,’ said the professor. As he put the glasses back on, his face and his attitude came back into focus. ‘I can’t be sure. Not under these conditions.’ This was apparently the only firm statement he was prepared to give.

  Bernie slumped. The director of the gallery looked smug.

  ‘Before you go, professor,’ said Friday, stepping forward and holding out her huge book. ‘I really enjoyed reading your book. Could you please sign my copy for me?’

  The professor looked surprised but also a little delighted to be presented with a copy of his own work.

  ‘Oh, of course,’ said the professor. ‘Not many young ladies ask me for autographs.’

  ‘What a shocker,’ said Ian sarcastically.

  Friday kicked Ian in the foot to get him to be quiet. She held open the book at the title page and handed it to the professor.

  ‘Do you have a pen?’ asked the professor.

  ‘Yes, but so do you,’ said Friday. ‘In your breast pocket.’

  The professor tapped his chest. ‘So I do. He took out a fountain pen and signed his name with a flourish.

  ‘Thank you,’ said Friday, taking back the book and turning it to herself to read. ‘I suspected you were a fraud and you’ve just given me proof.’

  ‘What?’ said Uncle Bernie.

  ‘You can’t insult Professor Abernathy,’ said the minister. ‘He is the world’s leading expert on High Renaissance masters.’

  ‘I know,’ said Friday. ‘His book was wonderfully insightful. But Professor Abernathy wrote it in 1979, when he was a much younger man. He may have been able to give an opinion then. But now, I think the only reason he is refusing to give an opinion is because he is as blind as a bat.’

  ‘How dare you!’ said the professor.

  ‘This girl is a disgrace,’ said the director.

  ‘Bats aren’t actually blind,’ said Ian.

  ‘I know that,’ said Friday. ‘I’m sure the professor isn’t either. But there’s a big difference between being able to see that there is a painting on a wall and being able to identify the trajectory of the microscopic cracks in the pigment.’

  ‘Friday, please explain yourself,’ pleaded Bernie. ‘Otherwise you’re about to get yourself, and me, in a lot of trouble.’

  ‘I know the professor can barely see,’ said Friday, ‘because he couldn’t even tell that he was looking through his magnifying lens the wrong way.’ Friday reached over the balustrade and picked up the eyepiece the professor had just used. She held it up to show everyone. ‘He was looking through the wide end. That wouldn’t magnify anything. It would make things look smaller.’

  Uncle Bernie reached for the lens and held it to his own eye. ‘Oh my gosh, she’s right.’ He handed the lens to the minister so he could see for himself.

  ‘This means nothing,’ protested the professor. ‘The girl is mistaken. I had it in my hand. She could not have seen this.’

  ‘We all watched you for thirty minutes,’ said Ian. ‘You definitely held the wide end to your eye.’

  ‘And it’s not the only evidence of your failing eyesight,’ said Friday. ‘I noticed that you’re a very dapper dresser, which is not surprising, given your great appreciation for fine arts. And yet you are wearing mismatched shoes of different colours.’

  ‘It was dark when I got dressed,’ said the professor. ‘A man is allowed to make a simple mistake like this, I think, when he is called upon in the night by Interpol and asked to fly to another country.’

  ‘I suppose,’ conceded Friday. ‘But there is also the fact that you just signed a written confession that you are blind right here, with your own fountain pen.’ Friday opened her book and turned the title page around to show everyone else in the room. The professor’s over-sized ink signature stood out. But there were several handwritten lines in biro written directly above it.

  ‘What you failed to notice, professor, is that I wrote, right here, the words . . . “I Professor Abernathy declare that I am legally blind”,’ read Friday. Everyone in the room leaned forward to get a better look. ‘I realise that English is not your first language so, just to be sure, I wrote these words four times over – once each in English, French, German and Latin. I reasoned that you must be able to speak at least one, if not all those languages, and yet you signed directly below without noticing. Only someone with atrocious eyesight would do that. And someone with atrocious eyesight would not be capable of properly assessing a painting’s authenticity.’

  ‘Professor, is this true?’ asked the minister.

  The professor looked like he wanted to deny it, but eventually he nodded his head.

  ‘Why didn’t you say something?’ asked Bernie. ‘Why agree to this whole thing?’

  ‘For his fee, of course,’ said the director scathingly. ‘A connoisseur can command quite a fee for his authentication services.’

  ‘Has he actually been giving opinions though?’ asked Friday. ‘There is a growing trend amongst art experts not to give opinions on valuable paintings because they don’t want to give evidence in court.’

  ‘It’s true, the easiest opinion is no opinion,’ confessed the professor. ‘Giving an opinion on the authenticity of a valuable painting exposes you to so much criticism, in the courts and in the industry periodicals. One is forced to have the same arguments over and over again for decades. It’s deeply unpleasant.’