The woman had what Max’s maman would call “a tidy mind”. Everything was immaculately folded and arranged. Spare clothes, a washbag, a hairbrush, a book. A stiff cream envelope, addressed to Celeste Le Blanc, 17 Rue de Tarasque, Le Vésinet, France. Max picked this up, examining the elegant swirling writing. It was very light – there couldn’t be more than one sheet of paper in there. She squinted at the stamps in the almost-darkness. They were from Istanbul.

Max reminded herself that letters are private business – even more private than suitcases. But then she pointed out to herself that it might be a clue. She argued with herself for a while, but it was already beside the point, because she had started taking the letter out of the envelope the moment she had seen the stamps. She unfolded it, and knelt close to the crack in the sliding door to read it:

My dear Celeste,

I enclose a photo as promised. I look forward so eagerly to your arrival. Take great care, my dear! Never has a girl been more precious.

Yours,

M x

Max checked the envelope, but the photo wasn’t there. Presumably it was tucked lovingly in a purse or a locket or something. Max was a bit disappointed. Celeste hadn’t seemed like she would carry photos around from people who called her a precious girl.

She reread the letter one more time. Take great care. Now that was odd. Why would Celeste need to take great care, if she was just on a normal train journey? Were she and her beloved M up to something dangerous?

She wrote Take great care on the woman’s page, and added Celeste Le Blanc at the top. She realized she hadn’t written anything for the others. Weirdly heavy case, but couldn’t see anything, she wrote for Ester. The diamond was tiny anyway, she remembered – so, now she came to think of it, the heaviness was neither here nor there. After a moment’s hesitation, she wrote Who needs that many socks? under Klaus. Which was a good question, but she couldn’t see what socks had to do with international diamond-smuggling networks. She had to admit that it was a disappointing set of notes so far.

But there was still Rupert. The train was about to pull into a station again, so Max had to scurry back to her bed for a while until the thrum of the train had started up once more. In the corridor, she paused to look out at the night. There were no lights here. Were they in Germany now, or Hungary, or in between in Austria?

No way of knowing. Max’s own ghostly face stared back at her from the window. She shivered, and got back to work, slipping silently into Rupert’s car.