'In that case, we might take the metro.'

'The metro?' she exclaimed, glancing towards the chauffeur.

'It is only a short trip.'

Her colour deepened.

'You have ridden the metro before?' he asked, incredulous.

'Father believes it is improper, and my aunt has a terror of being underground.' She tapped her gloved fingers upon the door, as if itching to open it. 'I suppose one would take the line from Opera?'

He nodded. 'There are only a handful of stations between there and Arts et Metiers.'

In truth, he had only ever taken the metro once before, but he had talked endlessly with the other apprentices about it. The fright and the thrill of hurtling through dark tunnels to emerge in another part of the city was something he was desperate to experience again. The boy in him grinned at Mademoiselle Clermont.

'Of course,' he said mischievously, 'if you too are afraid of being underground ...'

An impish smile was growing upon her face. She reached for the door handle.

'Emile,' she announced to the chauffeur, 'I shall be taking the metro to Lili's. I will telephone later, or ask that their driver bring me home, if the motor is not yet fixed.' She stepped under Gui's rickety umbrella. He took care to swivel it so that the leaks did not fall on her side. 'Don't mention this to my aunt, please,' she told the man. 'It would only worry her unnecessarily.'

The chauffeur nodded, face carefully blank. Mademoiselle Clermont's steps down the road were so fast that Gui had to hurry to keep up. The rain cascaded around their small shelter, until he could not help but stifle a laugh.

'Slow down!' he said. 'I can barely keep up with you.'

'I am sorry.' She was breathless, her smile huge. 'I feel like a prisoner escaping.'

In the warm pause that followed, Gui realized he had forgotten himself, had been addressing her informally. She did not seem affronted, but he switched back to the polite form when he spoke again.

'I met Luc recently, at the back door,' he said, as they slowed their pace. 'He told me that you hadn't been taking deliveries. Was that what you and your father disagreed about, a few weeks ago?'

The smile fell from her mouth.

'Yes,' she answered, 'amongst other things. My aunt told him that it was not appropriate for me to be doing any kind of work. He never listened to her before, but now ...' She seemed about to say more, but sighed, gave a half-smile instead. 'These visits to Lili are the only time I am allowed to myself.'

'Is it because of what happened in January?'

She nodded reluctantly.

'I am sorry.'

'Please don't apologize, Guillaume. If not for you, the situation might have been far worse.'

Place de l'Opera broke open before them, obscured and rain-softened. A few motor cars slicked around the road. They had to leap back as one flew past, sending a sheet of muddy water towards their shoes. Mademoiselle Clermont just laughed, peering in the direction of a set of marble steps.

'There's the metro!' She pointed. 'Are we truly going to take it?'

'If you wish.'

'Of course I wish! Quickly, before my boots are soaked through.'

They ran the remaining distance to avoid motor cars and carriages, b.u.mping into each other as they attempted to stay beneath the umbrella. The marble steps were treacherous with mud and rain. Mademoiselle Clermont steadied herself on Gui's arm, and together they made it to the ticket booth.

'Two single tickets, please,' Gui announced, 'to Arts et Metiers.'

He fished in his pocket for coins. Even a third-cla.s.s journey would come at the cost of eating that night, but he had never been more willing to part with money.

'Wait,' Mademoiselle Clermont was opening her purse. Firmly, Gui placed a small, perforated ticket in her hand.

'We are travelling third cla.s.s?'

'I thought you wished to see the real metro?' he said, and received a smile in return.

They descended grit-spattered steps, and it was as though a hot gullet was swallowing them up. The narrow tunnel curved and Mademoiselle Clermont gripped his arm as they emerged onto the platform. It was saturated with sepia light, a sunset in autumn captured and crammed into the globes that hung from the vaulted ceiling.

The rain was a great equalizer. Men in overcoats mopped their faces and cleaned eyegla.s.ses that were too steamed up to wear. Women removed dripping hats and attempted to brush them dry. No one noticed the young man and woman who stood arm on arm, although a close look would have revealed that they should not have been stepping out together.

The train arrived and Mademoiselle Clermont almost tripped over her skirts in her haste to board. During the short journey she pressed her fingertips to the window and stared in awe through her reflection into the black walls of the tunnels. Gui watched too, taking in the turn of her head and the curve of her cheek. It was with mutual reluctance that they left their seats when the train pulled squealing into their station.

'But I know where we are,' she exclaimed, running ahead as they emerged into the early evening. 'We are by the square. We have come all that way and it feels as though we've barely moved at all!'

'But we have.' Gui smiled, wrestling with the umbrella once more beneath the gla.s.s and iron shelter. 'That's the joy of it.'

The walk to Mademoiselle Clermont's destination was over far too quickly. The rain had eased, and it was almost pleasant in the grey, dripping evening. Gui told her about his work in the ptisserie, stories of initiations and accidents, which had her alternately amused and appalled. She demanded to inspect his cold pastry-making hands for herself, turning them over to touch the burn scars in way that made his stomach tumble like an acrobat.

'No one discovered you then, when you burned your jacket?' she asked as they ducked past an overflowing gutter.

'I'm safe for now, thanks to you and Patrice,' he said. 'Does that make us even?'

'Hardly.' Her eyes were shadowed beneath the brim of her hat. 'I still feel that I haven't thanked you ...'

There was a rattling from above and he pulled her to one side, thinking a slate might be tumbling from a roof. Instead, a head appeared from a fourth-storey window.

'Jeanne!' a girl's voice called.

'Lili!'

Mademoiselle Clermont waved at her friend and hastily shook out her skirts, wet through at the hem.

'Lili must have been watching the road,' she said quickly. 'Thank you for escorting me, Guillaume. It was a thrill.'

'It was my pleasure, Mademoiselle Clermont.'

The streets, which before had their own deserted charm, now stretched outward, extending the distance he had to walk alone.

'Goodnight then,' he said.

'Goodnight, Monsieur du Frere.'

Reaching the opposite pavement, he turned. She stood, looking over her shoulder. A doorman in white gloves appeared and held the door open, waiting for her to enter.

'What made you come back?' she called. 'That day in the flood?'

The s.p.a.ce between them filled with water and noise as the downpour began again. He tried to reply but his voice was lost in the weather.

Chapter Twenty-Seven.

May 1988 'So you're the one who left the note.'

The woman stands blocking the doorway. She looks like she is in her seventies; her grey hair is closely cropped and her eyes are sharp as flint. It is impossible to tell if she is amused or annoyed.

'I'm sorry to come unannounced,' I say awkwardly. 'There wasn't time to write and I couldn't find a phone number for Mr Lefevre anywhere.'

'We don't have one. We try to avoid communication like that. It's also why we moved here out of the way, so to speak.'

She is staring, as though she could make me leave her doorstep by willpower alone.

'I read your husband's book, the one about poste-restante letters,' I continue doggedly. 'I need his help, and I think I can explain something about one of his mysteries. I'm sure it would interest him.'

'Perhaps it would.' Her eyes focus out towards the harbour for a long moment. 'Since you've come all this way, you'd better come in. Please try to be quiet for now, he's taking a nap. I'll make some tea while you wait.'

The house smells like old cooking and shortbread and salt-damp from the sea wall. It's a small place, with narrow rooms and sharp corners. In the kitchen, a square window looks onto the waterfront. A mist is clearing, shafts of sunlight breaking through. The kettle whistles on the hob.

'So, what has you turning up on our doorstep like this?' she asks. 'You weren't specific in your note. It must be important.'

Hot water is poured over tea leaves, milk into a jug shaped like a cow. I have spent most of the morning improvising conversations in my head, but now that I am here, I don't know where to start.

'It's to do with my grandfather,' I say slowly. 'I found out recently that he made a terrible mistake when he was young man. I'm not sure exactly what happened, only that it haunted him for a long time. I think Mr Lefevre can help me find out what it was.'

A noise from the stairs draws her attention. An old man is climbing into the doorway. His eyes are sunken and clouded, but are bright with interest.

'Stephen, this is the young lady who left the note.' The woman adjusts a pair of reading gla.s.ses that sit crooked on his nose. 'She's here to talk to you about your work.'

She helps Lefevre into the room. His step falters and I see now that his whole body trembles. I feel a rush of guilt when I think about how I've barged in on this couple's well-ordered existence.

Perhaps sensing this, Lefevre smiles.

'No doubt my wife has tried to grill you over your intentions, young lady. Please excuse her, she used to lecture and has few people to terrify these days.' He extends a hand and I take it, feeling like an eight-year-old. 'Stephen Lefevre. Happy to talk through the book. I'm just surprised you found the d.a.m.n thing at all. Helen, I think we'll go to the study.'

'I thought you might. This way,' she directs over her shoulder.

Their slow progress takes us into a room at the front of the house opposite the kitchen. The light from the window is darkened by shelf upon shelf of books, built into the walls. They have even been stacked into the corners, volumes of different sizes fanning out like the spine of a fish. An oxblood sofa is jammed beneath the window, one arm buried under newspapers.

'Don't let her get away without a few difficult questions,' says Helen with a smile, closing the door.

The walls of the cottage are thick, and old. Their silence is the kind conducive to study, and hard to break.

'Miss Stevenson,' starts Lefevre, 'please humour an old man. Tell me about yourself, why you're here. In detail please. I meet so few people these days.'

I begin with my grandpa's death, why it devastated me so and how it led to the discovery of the photograph. I tell him about Ptisserie Clermont, the Allincourt letter, and, finally, the name 'du Frere'.

'In your book,' I say, searching for the library copy, 'when you mentioned the du Frere letters ...'

Lefevre has gone very still. His rheum-fogged eyes are fixed upon me. I start to worry whether he's still breathing until he lets out a long puff of air.

'J.S.,' he p.r.o.nounces clearly. 'J. Stevenson. How can you be sure?' He is holding himself back, but I can see the hope in his eyes.

'I can't,' I tell him honestly. 'But if there is a connection between Grandpa Jim and this du Frere, it's through the Ptisserie Clermont scandal. They were both involved. Whatever happened there, it caused a great deal of damage.'

'I met him once,' Lefevre is in a daze, 'your grandfather. I was a student in London and he'd just brought out his second work, one of his social histories. I never imagined it might be him.'

'I have to know what happened.' I'm surprised by the desperation in my own voice. 'Please, if you know what was in those letters he sent to du Frere, please tell me.'

'Can I see my book?' he asks abruptly.

I hand over the library copy. It falls open on the page I have marked. He peers down almost fondly at the words before tapping one of the paragraphs and motioning me to read.

'Being one of the best surviving examples of pre-war poste restante correspondence,' I recite, 'the majority of the collection is held in storage at The Musee de La Poste, Paris, except for one letter, which is in the hands of an archivist. Due to laws surrounding secrecy of correspondence, the seals on the envelopes have never been broken. As such, we are unlikely ever to know the story behind this remarkable collection ...'

I look up blankly. Lefevre is levering himself out of the armchair with great difficulty. I catch his arm and he thanks me, limping to a bookshelf where great stacks of box files are gathering dust. He is muttering to himself.

'Mr Lefevre?' I ask. 'Are you all right?'

He is attempting to lift the first file.

'Help me look, will you?'

I reach past him to grasp the box.

'Look for what?'

'For what!' He laughs. 'Dear me, you aren't very quick for a historian, are you?'

'The letter?' I almost drop the file on my foot. 'You have it? You're the archivist?'

'Of course I am,' he wheezes, 'what other fool would pay what I did for it at auction? It's filed away in one of these.' He indicates the stacks with frustration. 'I fear I lost heart after the book did so badly, but now you're here, we can-'

A cough racks his chest and he doubles over, unable to complete the sentence. I catch his arm and help him back to the chair, where he slumps down.

'We can open it,' he says eventually, 'the letter. It would be illegal for me to, but you're family, you're,' he gulps in air, 'next of kin.'