‘If she has a photo of their face,’ said Friday, ‘she can use Face ID to unlock their phone. She can access their banking app and take money while she’s pretending to take their picture.’

  ‘But that’s so complicated,’ said Melanie.

  ‘But you could do it in seconds,’ said Friday. ‘Pickpockets spend years practising to lift a wallet from someone’s pocket without them feeling it. This is the high-tech version. You could transfer $500 to yourself in seconds. If someone is on holiday in Paris, they’re spending money hand over fist every day. They might never notice.’

  ‘That’s crazy,’ said Melanie. ‘She can’t be doing that.’

  ‘It’s brilliant and I bet she is,’ said Friday. ‘Let’s watch her to see if she does it again.’

  It took another few minutes. Then they watched as a couple asked the girl to take a photo for them.

  ‘Here we go,’ said Friday.

  The girl took their phone, but as she reached across, she had her own phone in that hand. Friday definitely saw her tap the screen with her thumb.

  ‘You’re right!’ said Friday, ‘She took a photo of his face.’

  As the tourists got themselves into position, the girl held their phone above the picture on her own for a moment.

  ‘And she just unlocked it,’ said Melanie.

  They watched as the pretty girl held up the tourist’s own phone to take their picture. From where they were standing behind her, they could see she was actually opening the banking app.

  ‘That is so naughty,’ said Melanie.

  ‘It’s so blazon,’ said Friday.

  ‘A couple more,’ said the pretty girl. She had closed the banking app and was really taking their picture now.

  ‘What are you going to do?’ asked Melanie. ‘Call Bernie?’

  ‘This isn’t the crime we’re here to investigate,’ said Friday.

  ‘We’ve got to report her,’ said Melanie.

  ‘We can’t make a fuss,’ said Friday. ‘It would blow our cover.’

  ‘We have to do something,’ asked Melanie.

  ‘I know,’ said Friday. ‘Let’s go to the gift shop.’

  ‘Now is not the time for souvenirs,’ said Melanie.

  ‘No, not for the shopping,’ said Friday. ‘To talk to Agent Okeke.’

  Friday and Melanie found Agent Okeke in the Louvre gift shop, arranging a display of brightly coloured statuettes of the Venus de Milo into a rainbow pattern.

  ‘How can I help you mesdames?’ asked Agent Okeke, in such a hostile tone it was clear she didn’t want to be any help at all.

  ‘We’ve got something to report,’ whispered Friday, while pretending to look at a rack of tea towels. ‘We spotted a thief.’

  ‘Trying to steal the Mona Lisa?’ asked Agent Okeke. This had got her attention.

  ‘No, a thief who’s been using her mobile phone to hack into the phones of tourists,’ said Friday. ‘Then taking money from their bank account while pretending to take their picture.’

  ‘That’s not quite right,’ corrected Melanie. ‘She does actually take their picture.’

  ‘True,’ agreed Friday. ‘She’s taking money just before taking their picture.’

  Agent Okeke looked at Friday with unconcealed disgust. ‘You know, I used to be in the counter-terrorism squad. I am trained in how to disarm bombs, subdue terrorists and smash my way into multi-storey buildings. It’s bad enough that I have been reduced to surveillance in the art crime unit. I absolutely refuse to be dragged down even further into wasting my time on virtual pickpockets and the tourists foolish enough to fall for their scams.’

  ‘That’s not very professional,’ said Melanie. ‘Surely it’s your job to help people.’

  ‘No, it’s not,’ said Agent Okeke. ‘It’s my job to arrest bad people. And if they won’t let me arrest them, sometimes I get to shoot them.’

  ‘How did you ever pass the psych test?’ asked Friday.

  ‘Easily,’ said Agent Okeke. ‘I lied. Interpol needs agents like me. We can’t all be wishy washy hand-holders. They need some of us to wrestle down armed gunmen and throw ourselves on bombs.’

  ‘We can’t let this girl get away with it,’ said Friday.

  ‘Yes, you can,’ said Agent Okeke. ‘It’s called maintaining your cover. You’d know all about it if you’d ever been trained properly.’

  ‘Brianna,’ called the shop manager. Friday had forgotten that Agent Okeke had a first name. ‘If you’ve finished chatting with your young customers, I need you to fetch more Mona Lisa coffee mugs from the stockroom.’

  The manager turned on her heel and strode away.

  Agent Okeke gritted her teeth. Friday noticed her hand clench around the throat of the Venus de Milo statuette she was holding. ‘Oui, madame,’ she said with a very false smile.

  ‘Aaahhh!’ came a despairing wail from the entrance to the shop. Friday and Melanie turned to see an older Nigerian woman in a fabulous hot pink gele headscarf staring at Agent Okeke. ‘Your brother told me you were here and I did not believe him!’

  ‘Oh no,’ said Agent Okeke.

  ‘Someone you know?’ asked Friday.

  ‘My mother,’ muttered Agent Okeke.

  ‘How lovely!’ said Melanie. ‘It’s nice she came to visit you at work.’

  Mrs Okeke strode into the store and poked Agent Okeke in the chest. ‘Your father and I did not struggle to bring you to this country so you could be a shop girl!’ she declared.

  Agent Okeke didn’t exactly cower, but something about her body language changed. The presence of her mother seemed to make her shrink.

  ‘It’s not like you paddled across the Mediterranean in a boat,’ grumbled Agent Okeke. ‘You flew here business class when Peugeot hired Papa as an engineer.’

  Mrs Okeke chose to ignore this point and stick to emotional blackmail. ‘You did so well at school and university. You could have done anything!’

  ‘I’m doing what I want,’ said Agent Okeke.

  ‘Selling over-priced postcards?!’ demanded Mrs Okeke, flicking her hand dramatically in the direction of the postcard rack on the wall. ‘Has Interpol fired you now as well? Is this the only job left you can get?’

  ‘Shhh, Maman, this is not the time or place,’ said Agent Okeke. ‘I’ll come over to dinner and explain everything.’

  ‘You are always too busy to come and see me,’ said Agent Okeke’s mother.

  ‘I eat dinner at your house every Sunday,’ said Agent Okeke.

  Mrs Okeke sniffed and looked away. ‘Only because my cooking is so good.’

  Agent Okeke leaned in and spoke to her mother softly in a different language. ‘Uwa, ina yi wa ’yan sanda kasuwanci a asirce. Kuna buatar barin.’

  Whatever she said, it caught her mother’s attention.

  ‘Yan sanda?’ said Mrs Okeke, suddenly more serious.

  Agent Okeke nodded.

  ‘Oh,’ said Mrs Okeke.

  ‘What was that?’ Melanie asked Friday.

  ‘I don’t know,’ said Friday. ‘I presume they’re talking Hausa. In Niger, it’s the second most common language after French.’

  ‘I’ll call you later,’ Agent Okeke told her mother.

  ‘All right,’ said Mrs Okeke.

  Agent Okeke kissed her mother on the cheek. ‘And tell Usman he’s an idiot.’

  ‘I will,’ agreed Mrs Okeke, kissing her back. ‘I definitely will.’ She swept away.

  ‘You can’t have family members come here and create a scene,’ said the shop manager. She hadn’t had the courage to point this out while Mrs Okeke was still in the store. Now Agent Okeke’s mother had left, the shop manager felt safe to bully her employee again. ‘I’m going to have to write this up.’

  Agent Okeke turned to her manager. There was no hint of a little girl about her anymore. She was back in professional mode. ‘I de-escalated the situation quickly and persuaded my family member to leave so that we could resolve the issue at an appropriate time and place,’ said Agent Okeke. ‘I fail to see how I could have handled the situation better. I will be filing a full report with my union representative to document the incident, including your attempt to threaten me – and these two customers are my witnesses.’

  Melanie smiled at the manager. ‘And we’ll be such good witnesses,’ said Melanie. ‘My family is very wealthy, so I’ll hire the best attorney to make sure our statements hold up in any industrial tribunal.’

  ‘There’s no need for any of that,’ said the manager. ‘Just make sure you fetch those coffee mugs.’

  The manager stalked off.

  Agent Okeke turned to Friday and Melanie. She didn’t speak. She just pressed her lips together and glared.

  ‘Are you trying to say “thank you” but you can’t bring yourself to say the words?’ asked Friday.

  ‘I hate teenagers,’ muttered Agent Okeke.

  ‘I love your mum,’ said Melanie.

  Agent Okeke made a grunting noise and went over to get the mugs. Friday felt a pang of jealousy. She wished she had the type of mother who stormed into public spaces and yelled at her in a totally humiliating way. While it was undoubtably painful for Agent Okeke – it was an impressive act of love to behold.

  When Friday and Melanie got back to their dorm that afternoon, Sophia was already sitting on her bed. Watercolour paints were spread out all around her as she added colour to the drawing she had done that morning.

  ‘There’s a note for you,’ said Sophia without looking up.

  ‘Where?’ asked Friday in surprise.

  ‘Oh, Friday, that’s not very observant of you,’ said Melanie, reaching past Friday’s head to where a note was pinned to the door just inches from her face. The note was folded up and had just one word written on the outside. ‘Friday’.

  Friday opened it out.

  Meet me at 9.30 at the bottom of the fire escape. Your secret admirer.

  Friday blushed. She recognised the handwriting. It was Ian.

  ‘We have a 9 pm curfew,’ said Sophia. ‘You’ll be breaking the rules if you go.’

  ‘How do you know what’s in the note?’ asked Friday.

  ‘I read it,’ said Sophia, briefly glancing up. ‘Just because I’m an art student doesn’t mean I can’t read.’

  ‘But it’s a private note,’ said Friday.

  ‘It was an unsealed piece of paper pinned to a door in an open area,’ said Sophia with a shrug.

  ‘But it was clearly addressed to me,’ said Friday.

  ‘It said “Friday”,’ said Sophia. ‘But how was I meant to know it meant Friday the name? It could have meant Friday the day. As in, a note about something happening on Friday. Friday isn’t really a name, so for me to assume it was indicating a specific person would be ridiculous.’

  ‘Not if one of the two people you share a room with is called Friday,’ said Friday.

  ‘Buy your secret admirer a box of envelopes and it’ll never happen again,’ said Sophia.

  ‘There’s a kettle in the kitchen,’ said Melanie. ‘If he starts using envelopes we can steam them open.’

  ‘Melanie, don’t encourage her,’ said Friday.

  ‘So who is your secret admirer?’ asked Sophia. ‘If you tell me all the juicy details, I promise not to rat you out to Kate.’

  ‘I don’t know,’ said Friday. ‘It’s secret.’

  ‘You’re lying,’ said Melanie. Melanie had a gift for knowing when anyone was lying. Although in this instance, being Friday’s best friend, Melanie could have deduced that she was lying simply by using common sense.

  ‘Ah, Friday,’ said Kate, suddenly appearing in their doorway. ‘Glad to catch you. Look, I hate to be a drag, but if you’re going to sneak out to see your boyfriend, or girlfriend – no judgements here – then could you be a bit subtle about it? Use the fire escape. It’s just that there is a curfew and I need plausible deniability.’

  ‘You read my note too?’ asked Friday. ‘Does no-one here have any respect for privacy?’

  ‘Well, I’m the RT,’ said Kate. ‘I need to know when people are sneaking out and breaking curfew so that I can make sure I’m not there to see them do it. If I see you, I have to stop you. Then I have to fill in an incident report and I’m in the middle of an oil painting of the Tuileries Garden.’

  ‘How lovely,’ said Melanie.

  ‘I know,’ agreed Kate. ‘It’s just the sort of painting I’ll be able to get some cashed-up tourist to overpay for, which is why I haven’t got time to do my actual job responsibly.’

  ‘It’s important to prioritise,’ agreed Melanie.

  ‘I broke the lock on the window by the fire escape so it’s easy to jimmy open with a butter knife,’ Kate told Friday. ‘Here’s a butter knife.’ She reached into the pocket of her painting smock and pulled out the utensil. ‘I’ll make sure I’m listening to really loud music in my room at nine twenty-five.’

  ‘Okay,’ said Friday. Kate disappeared back into her own room. Friday stood looking at the butter knife in her hand. ‘Artistic people are surprisingly similar to theoretical physicists. They’re so obsessed with their work, nothing else they do makes any sense.’

  When Friday climbed out through the living room window onto the fire escape at 9.28 that evening, the first thing she noticed was that the steel railings were freezing cold. December in Paris was nippy during the day, but as soon as the sun went down the temperature dropped like a stone. It was also dark and Friday’s eyes hadn’t adjusted properly yet. It was disconcerting that the only thing beneath her feet was a steel grate that she could see through. The five-storey drop made her stomach lurch. Friday clutched the railing tightly.

  Friday did not care for heights. Or anything that involved coordination. Walking down a fire escape without looking at her feet was going to be a challenge. She edged around the landing until she was standing at the top of the first flight of steps.

  ‘I can do this,’ muttered Friday, trying to convince herself by saying the words out loud. She took a deep breath, closed her eyes and began her descent. She concentrated on counting each step. Math always took her mind off things. She didn’t like the way the fire escape creaked each time she put down her foot. Thirteen. There were thirteen steps before she arrived at the turn in the stairs. She pivoted, eyes still closed, and took the next thirteen to the fourth-floor landing.

  ‘Hello.’

  Friday flinched back. There was a voice centimetres from her face. When she opened her eyes – it was Ian.

  ‘You!’ said Friday.

  ‘Who did you expect?’ asked Ian. ‘Do you get lots of notes asking you to meet someone on the fire escape at nine thirty?’

  ‘I thought I’d meet you at the bottom,’ said Friday.

  ‘I guessed you might have trouble with the heights,’ said Ian. ‘This is my floor. I thought I’d wait for you here and help you get down the rest of the way.’

  This would have been sweet if the twinkle in Ian’s eye hadn’t made Friday suspect that he was laughing at her.

  ‘I was managing,’ said Friday.

  ‘Another three flights and you would have been traumatised,’ said Ian. ‘We can’t have you in shock. We need your brain in top form.’

  ‘Why?’ asked Friday. ‘What do you need my brain for?’

  ‘We’re going to the Louvre to meet Bernie,’ said Ian. ‘The world’s leading Leonardo da Vinci expert has just flown in from Berlin. He’s going to examine the painting tonight after the gallery closes.’

  ‘Oh,’ said Friday.

  ‘What?’ said Ian.

  ‘Your note said this was a date,’ said Friday.

  ‘Did it?’ said Ian.

  ‘Well, it implied it,’ said Friday.

  ‘We’re meant to be undercover,’ said Ian. ‘I couldn’t leave a note saying that we had to meet an art expert to determine if the Mona Lisa had been stolen. What if one of your dorm mates read it?’

  ‘They did all read it,’ said Friday.

  ‘There you go,’ said Ian. ‘I was being subtle.’

  ‘Okay,’ said Friday.

  ‘You’re disappointed this isn’t a date, aren’t you?’ said Ian. He was definitely smirking now.

  ‘Of course not,’ said Friday. ‘Dates are anachronistic. Redundant, really. It’s silly in this age of post fourth-wave feminism to entertain outdated notions of how . . .’

  Ian leaned forward and kissed her.

  ‘What was that for?’ asked Friday.

  ‘To make things a little date-ish,’ said Ian. ‘Obviously, I am a post fourth-wave feminist myself, but I like to respect ancient cultural traditions. Come on, we don’t want to be late for Bernie.’

  Ian took Friday by the hand and led her down the stairs. She forgot that it was a fire escape for a moment. With Ian’s fingers wrapped around hers, her feet went into autopilot. All her brain could focus on was how nice it was to hold a warm hand after holding the cold steel railing for so long.

  ‘Do you want to grab some hire scooters?’ asked Ian. ‘It will be quicker.’

  ‘Are you kidding,’ said Friday. ‘You know my sense of balance. I’m not going to be able to help the investigation if I’m roadkill.’

  ‘We could share one,’ said Ian. ‘That would be very date-like.’

  ‘Can’t we just walk?’ said Friday. ‘I know the idea of a couple sharing an e-scooter seems romantic. But there will be nothing romantic about the trip to the emergency room when I inevitably break my wrist.’

  ‘Fine,’ said Ian. ‘I tried.’

  When they arrived at the Louvre, the security guard at the Passage Richelieu entrance was expecting them. Ian and Friday flashed their Interpol IDs and they were soon inside.

  ‘Where to?’ asked Friday.

  ‘The Mona Lisa room,’ said Ian.

  ‘Yes, but where’s that?’ said Friday.

  ‘I thought you and Melanie went there this afternoon?’ said Ian.

  ‘We did, but we’ll never find it again without a map,’ said Friday. ‘This place is a maze.’

  Ian looked perplexed. ‘It’s just across the main lobby, up the east staircase for two floors, right towards the antiquities wing, right again past the headless statue of Winged Victory of Samothrace, down the corridor and left into room seven hundred and eleven – Italian paintings.’