Their brownstone looks similar to the others on the street – beautiful, old and well kept. They have miniature evergreens and ivy in the window boxes, an American flag hanging from the second storey, an autumn wreath on the door, and a silver filigree mezuzah affixed to the door frame. The curtains are drawn.

I knock, hoping for an answer from the Secret Service or whatever organization it is that watches over this nation’s more famous senators. No one answers. I knock again, and a stocky man with broad shoulders, stylish grey hair, and a security earpiece opens the door. “May I help you?” His voice is as solid and sturdy as his appearance.

“Isla Martin.” My own voice trembles. “I’m Josh’s girlfriend. From France? I know he won’t be home until tomorrow, but that’s when I’m leaving, so I was hoping you could pass this along to him.”

“I know who you are.”

“You do?”

The tough guy act is dropped for a moment. He smiles, and it’s surprisingly warm. “I’m paid to know that.”

“Oh.” My cheeks turn pink. “Well, would you please give this to him?”

He takes the package from me. “Sure. But I’ll have to scan it for explosives first. As long as it passes, he can have it upon his return.”

I laugh.

“That was a serious statement. All parcels are checked.”

My cheeks deepen into red. “Of course. Thank you, sir.” And I scuttle away.

The next night, when I check my phone in Paris, I have a text from an unknown Manhattan number. He doesn’t mention the return of the manuscript – nor the fact that I left its pages wildly out of order – but he does say this: I can’t believe how much I missed your scent. Merci for the scarf, my sweet rose.

Chapter twenty-four

The pallor of winter further overcasts the already grey city. Olympic rings, bright and colourful, provide the only visual relief. They’re plastered on every advertising surface, including the sides of entire buildings. This February, the Winter Olympics will be in the Rhône-Alpes region of south-eastern France, though, by the adverts, you’d never know they weren’t in Paris proper. The French athletes are the stars of the posters, naturally, but a few of the biggest names from other countries have also made the cut.

Kurt and I exit the Denfert-Rochereau métro station and pass a larger-than-life poster of a fierce-looking American figure skater named Calliope Bell.

“Who do you root for?” I ask. “The Americans or the French?”

The Olympics have always been a source of mixed feelings for me. I know I’m supposed to feel a sense of national pride, but which nation? I feel loyalty towards both.

Kurt glances at the poster. “I root for the best athlete in each event. They don’t have to be American or French.”

“So…you root for the winner. Isn’t that sort of cheating?”

“No. I root for the person who appears to be working the hardest.”

It’s a strange answer, but it’s still a good one. It gives me something to think about. We enter a small, nondescript, dark-green building. It’s empty of tourists today. We pay a guard, pass by another guard, and tromp down a spiral staircase until we reach a long, low tunnel. Water drips overhead. We splash through shallow puddles. It’s cool down here in the catacombs, but not cold, because there’s no wind.

Kurt points towards a tunnel that’s been gated off from the public. “Have I told you there are over a hundred and eighty miles of abandoned tunnels in Paris?”

Yes. He has told me. He’s been talking about the tunnels non-stop since our return to school. In the last month, he’s gone from intrigued to full-blown obsessed. While I sat in detention, he read everything about them – the métro tunnels, limestone quarries, utility lines, sewer systems and crypts – which together make one of the most extensive underground networks in the world.

He wants to map it, of course.

It’s odd how the two most important people in my life are both interested in maps. Kurt in the most literal sense. But Josh, too. By chronicling the major events in his life, Josh is also drawing a map. I wonder how long I’ll be a part of it. Where and when does my story fall away from his?

“Maps of the tunnels exist,” Kurt continues, “but none of them are complete. And they’re often purposefully misleading to keep people away.”

Exploring them is illegal, and as a bona fide rule-follower, this is Kurt’s greatest frustration. But that hasn’t stopped others from doing it. The tunnels attract all types, known collectively as cataphiles – historians, graffiti artists, ravers, cavers, musicians, treasure hunters. Some have gone into the tunnels to restore priceless art. One group ran an underground cinema. The French resistance hid down here during the Nazi occupation, and then the Nazis used the exact same tunnels to flee.

It won’t be long before Kurt’s obsession overpowers his need to follow the rules. But, for now, he’s been visiting and revisiting the legal part – les Catacombes. More than six million bodies were carted down here in the late 1700s, and the endless walls of their stacked bones are available for viewing at a small fee. Some of the bones are arranged into simple shapes like crosses or hearts. Some are arranged by size or type. But most of them were thrown in at random for practicality’s sake.

As a child, I found the catacombs frightening. As I got older, they grew fascinating. Now they’re almost tranquil. But maybe all of these skulls are just reminding me of a certain someone’s tattoo. I sit on a folding chair that’s meant for a guard while Kurt surreptitiously pokes around.

It feels fitting to be here. Quiet yet undeniably gloomy, much like my state of mind. Since Thanksgiving, I’ve finished detention, toiled over homework assignments, and crammed for exams. I haven’t been reading for fun. Schoolwork is better at distracting me from the enforced silence between Josh and myself.

How did my parents live before texting? Before the internet? I’m used to knowing things and all of this unknowing is driving me mad. We send each other handwritten letters, but it takes so long for the mail to arrive that he’s often in the wrong city by the time my correspondence reaches him. His family has been travelling non-stop between New York and DC.

I think he’s in DC right now. At least, that’s where I mailed his Atheist Hanukkah present, a box of his favourite pre-packaged French foods. If only I could talk to him, I know I’d feel better. I carry his letters in my bag, I use his stein as my everyday drinking glass, and I’ve hung up his drawings beside my bed – the one of my necklace from the first week of school as well as the Sagrada Família’s dove-covered tree, which he gave me after he was expelled. But he still feels so far away.