She was bringing the milk cans up from the barn after milking one morning when a powerful blast made her dive to the ground and cover her head, nearly spilling the milk. It was followed by a deafening roar as something streaked overhead, soaring high into the sky. The others heard it too and came running outside to look up.

“What kind of weapon was that?” Ans wondered aloud.

Leeuw answered her question when he came a few days later. Ans stood inside the barn with the others to hear about it. “Hitler has a new secret weapon called a V-1 rocket,” Leeuw told them. “It doesn’t require an airplane to deliver the explosives and can be launched from the ground at any target, any time of day or night. The Allies can’t stop these rockets or shoot them down like other enemy aircraft. They have to find out where the launch sites are and target them.”

“They launched a rocket nearby,” Ans told him. “We heard it the other morning. It sounded very close, east of here.”

“That matches the other evidence we have. These rockets will cause a lot of death and destruction before this war is over.”

“I want to help,” Ans said. “I used to gather military information and sketch maps for the Allies. I know the codes and what to look for. If you let me go back to Leiden —”

He held up his hand, stopping her. He led her away from the others to the laundry tubs she’d abandoned when Leeuw had arrived. “Ans, I need to tell you something,” he said when they finally halted. Her heart thudded as she steeled herself for bad news. She wasn’t expecting what he told her. “Herman Huizenga and his brother Aalt have been arrested.”

“What? . . . That can’t be! . . . Please, that must be a mistake! Did they find out he was hiding people?”

“No, something worse. The bank where the Huizenga brothers worked has been funneling money to the underground. They’ve been underreporting the Jewish assets that the Nazis confiscate and using the money to help Jews in hiding.”

Ans admired the professor more than ever, yet she was terrified for him. “What will happen to them?”

“We don’t know. They and everyone who worked at the bank are in the prison camp in Amersfoort.”

“Was his wife also arrested?”

“No.”

“She isn’t well. She shouldn’t be alone. Are the cook and housekeeper still there?”

“Yes, their cover story is holding up for now. But it isn’t safe for anyone else to hide there —or for you to go back. The house might be watched.”