“So why didn’t she just buy it? She was rich.”

“Maybe she was planning to. That’s why she came to Lucerne – to outbid Hummel and the others. But somebody got to it first,” Amy said.

“Hummel?”

Amy’s fingers flew as she typed an e-mail. “I’m asking the Attleboro group to research Hummel. Then we’ll dig a little deeper into Jane Sperling. I just have a feeling these two are connected somehow.”

Dan knew better than to argue with Amy’s feelings.

“Look, research isn’t my strong suit,” he said. “How about I go out and gather some more supplies for us?”

Amy waved a hand. She was already gone, lost in the 1930s and the lives of people she’d never meet.

“Back in an hour,” Dan said.

He had already done a quick search on the train, using his smartphone. He knew he didn’t have much time. He’d managed to gather seven ingredients in Italy. If he could find a few here in Basel – three, at least – he’d have one-quarter of the serum ingredients. And some ingredients he could save for last, things he could pick up easily at any grocery store: salt, mint, honey … those would be easy.

He blended in like a tourist in his jeans and jacket and baseball cap. He stopped in a pharmacy and in five minutes flat had left with a small bottle of iodine.

Amy would be furious – and concerned – if she knew he was assembling the serum. She was afraid of it. She would never allow him to take it. She would say it would change him – possibly kill him.

What she didn’t understand was that he didn’t care.