The Bosfor was moving.

The Bosfor was moving, and Sister Marguerite was not in her seat.

They picked up speed. Bucharest Nord rushed away from them as the Bosfor pulled out, and out, and out, on unstoppably to Istanbul.

She’s probably just sitting in the wrong seat, Max told herself. But even though she was an optimist, there was a great yawning pit in her gut, because she didn’t believe that at all. She hurried up the train, scanning all the cars, praying for a glimpse of crumpled wimple, of long grey sock. She hurried back down again. She did that twice more, as if she might somehow have failed to notice the world’s tallest nun. Then she sat back down in her seat, and cried.

There was one other person in her car, a lady dressed all over in a powdery purple. She half smiled, half frowned at Max in a concerned bid to be kind, and said something in a soothing voice. Max couldn’t understand her – she was speaking Turkish – but it wouldn’t have made any difference, unless she happened to be saying, “Don’t worry, Sister Marguerite has not been hurt by whoever pushed Rupert off the train, and they will not be hurting you either, and everyone is safe, and I have got your red velvet armchair here for you.” And she probably wasn’t saying that.

For the first time, Max didn’t care who it was who’d stolen the diamond, and pushed Rupert, and vanished Sister Marguerite. She just wanted them to stop.

But she realized, as she took some gulping-great breaths, that knowing who they were truly mattered now. She didn’t know what they had done to keep Sister Marguerite from the train, but she had to find out, and somehow make things all right again. Marguerite had promised to keep Max safe, but Marguerite was gone. It was up to Max.

So she took some more of the gulping breaths, held on to her plaits, and thought.

What had Sister Marguerite realized? Ester knew Great-Aunt Elodie, and had visited Berlin, to bid for a crystal penguin. What had that told her?

And what had she left the restaurant car to look for? Something in their sleeping car – which had also become Ester’s sleeping car. Whatever it was, Klaus Grob – Die Eiserne Hand security – had put himself firmly in the way. Max would bet the heartbreak diamond itself that the answer was waiting in Ester Rosenkrantz’s luggage. She would have to take another look. And the sooner the better. She didn’t fancy sneaking about at night, when anyone could be waiting for her in the shadows, ready to get rid of another nuisance. She would go now.

But how to distract Ester and Klaus? She needed an idea, and fast, but she was still having trouble thinking in straight lines.