Just a few months after Japan's bombing of Pearl Harbor, Los Angeles came under an air attack of its own, but from who, or what, remains a hotly debated topic. Some people, including a former FBI agent and UFO investigator, believe it may be the first and best-documented case of an extraterrestrial visitation. Others are more skeptical. One thing is certain. Something incredible happened on February 25, 1942. Now, with recently declassified top-secret documents and startling new evidence, we attempt to unlock this 73-year-old mystery.