In the fall of 1918, the streets of Boston emptied as paranoia about the deadly Spanish flu spread. And, as World War I raged on, the enemy seemed to be lurking everywhere. Newspapermen and vigilante investigators aggressively sought to discredit anyone who looked or sounded German. War Fever explores this delirious moment in American history through the stories of three men: Karl Muck, the German conductor of the Boston Symphony Orchestra, accused of being an enemy spy; Charles Whittlesey, a Harvard law graduate who became an unlikely hero in Europe; and Babe Ruth, the most famous baseball player of all time. Together, they offer a gripping narrative of America at war and American culture in upheaval.