“Ideally, we needed a new smuggler – someone totally unconnected, and totally above suspicion. Which is difficult, my dear.” She sighed sweetly at the unfairness of her life. “So, I tried calling your parents. I knew they would never deign to come themselves, but if they sent one of the children, that would be perfect. Nobody would never expect a child.”

“I wasn’t very hopeful, my dear, knowing your family. I was up all night dreaming up other schemes. But then they sent you – the youngest! The perfect smuggler. So I sent a hat, and all Suzanne had to do was open it up at the post office, add the bobble and send it on its way.

“It was all set up perfectly,” she said. Her little hands clenched in their gloves with frustration. “Suzanne’s theft went flawlessly, she slipped it in the bobble without any trouble, and I reminded your dear mother to make absolutely sure you packed the hat. All you had to do was get from A to B, while Suzanne kept an eye out. I didn’t think you’d be a meddler. None of the rest of your family are.”

“The photograph,” said Max, “That you sent to Cel – to Suzanne. It was of me, wasn’t it?”

Great-Aunt Elodie inclined her head once: yes. “One of the photos that your dear mother so thoughtfully sends me every Christmas.”

“M. For Elodie Morel,” murmured Max, talking to herself now. Take great care, my dear! Never has a girl been more precious. The girl in the letter wasn’t Suzanne. It was her, Max.

No wonder Suzanne had seemed so angry when Max had nearly left her case behind on the Kálmán Imre. All that time she spent standing around in train corridors, she had been keeping watch on Max’s car. And she hadn’t been following Ester and Klaus at all, that day in Budapest – she had been following Max. Following the heartbreak diamond.

Great-Aunt Elodie Morel and Max Morel both sat silently, both with brains whirring, both trying to plan their next steps – more alike than Max knew or would want to admit. The room was very still and quiet. Nothing rattled or chugged or swayed. Max wished she was still on a train somewhere, speeding off into possibilities: she seemed to have hit a dead end.

She remembered the park in Budapest, where she had felt as though all of them were tangled together, in ways that she couldn’t quite unravel. Now she saw how the tangle had happened: Marguerite was chasing a diamond, Ester and Klaus were protecting their diamonds, Suzanne was guarding a diamond – and Max had a diamond, all along.