Soon after the Japanese surrender in 1945, Hilsman was part of an OSS group that staged a parachute mission into Manchuria to liberate American prisoners held in a Japanese camp near Mukden. There, he found his father, who became one of the first prisoners to be freed. His father asked as they hugged, "What took you so long?" At some point, Hilsman was promoted to captain. (Decades later, Hilsman related his wartime experiences in his 1990 memoir "American Guerrilla: My War Behind Japanese Lines".)