When information is buried deeply in the black, it soon may be lost to the very governments that first held it. Such is the case for three incidents of alien spacecraft arriving on Earth in the mid Twentieth Century. But the information was not lost, only removed from government control and brought into a very secret organization that would work for many decades to prepare for the arrival of an alien fleet that they knew was coming to claim Earth for their home.

Nebula tells how this group of scientists, engineers, industrialists, and warriors prepared to defend Earth from a threat that...