From the #1 New York Times bestselling author of the Penn Cage series comes a gripping World War II thriller, Black Cross. It is January 1944—and as Allied troops prepare for D-Day, Nazi scientists have developed a toxic nerve gas intended to repel and wipe out any invasion force. To salvage the planned assault, two vastly different but equally determined men are sent to infiltrate the secret concentration camp where the poison gas is being perfected on human subjects. Their only objective: destroy all traces of the gas and the men who created it—no matter how many lives may be lost…including their own.