Hank Brandt has received information no spy chief ever wants to hear: one of his operatives has disappeared, and with him, valuable intelligence about a Nazi rocket program. This threat grows more dangerous by the day as Brandt rushes to gain information about its operations and hopefully, its weaknesses. But he can't put the pieces of the failed operation back together alone, and calls upon his most cultivated spy, Sam Abel. Meanwhile, behind enemy lines, Lothar Eichler feels the foreboding winds of change against the shore where the Nazis hide their most coveted secret. The spy-hunter Aksel Falke has recruited Eichler to root out future subterfuge on the island. Both men's superiors have begun to inquire about a troublesome American saboteur who has brought such a great deal of frustration to the Reich. Sam is losing ground fast, but finds an unlikely ally in an Austrian priest, Father Jan Lukas, who is hell-bent on sabotaging the Nazis in any way possible. But will his help be enough? Sam will once again be tasked with inserting himself behind enemy lines, this time, before the sky falls.