Beginning in the summer of 1944, at the height of World War II, The Man Called X was originally a kind of "FBI" program. The series soon developed a more international approach, however, featuring danger, intrigue, and romance in exotic settings. On any given Saturday or Sunday evening, Wendell Niles would say, "Wherever there is mystery, intrigue, romance, in all the strange and mysterious places of the world, there you will find "The Man Called X".