Then she had a thought, and the thought was enough to make her get up and clean her blackened hands, even though they still shook; and go to her carriage for clean clothes that wouldn’t give her away with the stink of roses; and hasten back one more time to the carriage of Klaus Grob and Ester Rosenkrantz, before Ester recovered from the spider.

This was the thought:

She had never noticed that there was more than one way into a train before. It had never occurred to her to look. Would she have noticed if there was more than one way into a suitcase? And that suitcase had been much heavier than it should have been.

Celeste was still in the corridor – as always – and there was no way for Max to avoid her gaze. She watched Max hurry back and forth, eyebrows raised. “Busy day, Max?” she asked.

But Celeste was a lot less scary now that Max had spent time clinging to the roof of a train. So she just said “Yep!” and charged past, leaving Celeste to stare after her, and wonder.

Ester and Klaus were still gone: the spider had done well. Everything but Ester’s pear drops was in exactly the same position. Klaus must have just reached in and grabbed them, not spotting the glass. Max pulled the suitcase out again.

She heaved it on to each side in turn, searching.

There! A long, thin hole, hidden on the bottom edge. A hole that just might take a key.

Ester and Klaus had left their coats behind. Max searched the pockets. Klaus’s were no use, and Ester’s had a lot of sticky pear drops. Max was so close, but still so infuriatingly far. She tried putting her chin on her hands to channel Sister Marguerite, and she thought.

If she had a key like that, she would want to keep it with her at all times. Not just in a coat or a skirt or anything, that you had to take on and off. It might, she thought glumly, be with Ester right now. Probably on a chain round her neck – although, no, Max would have seen it nestled among her fabulous necklaces.

There was a click-clicking noise from the corridor, and Max tensed – but it was just a grumble from the train, not a tapping stick. The stick was still here, anyway, Max remembered. Ester must really have been scared, to race off without it; she always had that stick with her.

And then, half a second later, the penny dropped.

Max grabbed the stick and twisted at the silver top. Like a dream, it turned, then eased away from the wood. Peeking out from the bottom of the silver was something long, thin, and gold, with little ridges along the edge. Max slid it out of its hiding hole. A tiny key.