She stopped laughing when Annika tapped her on the shoulder.

“Max?”

“Yes?”

“Where are the others?”

“What do you mean?”

“We’ve been here for two hours and thirteen minutes. Surely even Klaus has finished eating lunch by now.”

“You’re right. Maybe they decided to go someplace else.”

“That doesn’t make sense,” said Annika. “We agreed to meet here.”

“Well, the restaurant is only a few blocks away. We can walk back. See if they’re still there…”

Annika nodded. “A wise and prudent suggestion.”

They thanked the curators of the Einstein Archives.

“We hope to return with our classmates,” said Annika. “If not today, then someday soon.”

They reached the lobby of the building.

And saw two suspicious men in black suits lurking under the covered breezeway outside.

One was staring at his phone, reading its screen. The other looked like he was waiting for someone to exit the building.

“Do you know the phone number for the CMI?” Max whispered to Annika.

“Yes. I have it programmed into my smartphone.”

“Good. We need to call Charl. No, wait. Isabl. She’s a much faster driver.”