3 billion years ago, an alien evolution experiment began, then they ended the age of dinosaurs to protect that experiment. Later, they performed three human makeovers—Jesus Of Nazareth, Galileo, and a 72 year old man named Sam. In 2016, a spacecraft lands in Virginia carrying Sam—now The Emissary—who reveals an hypothesis to be tested—Science as an organizing principle is compatible with species survivability and longevity. With Sam is BC. who appears as a platinum rod, a wooden staff, a Border Collie, and a giant tarantula. Sam explains the experiment is threatened by religious fundamentalism, so to usher in an Age Of Science, Sam confronts a variety of believers and unbelievers. But superstition is hard to overcome, and when fanatics attempt to assassinate them, BC wreaks havoc. Then Sam reveals an unimpeachable witness, whose testimony rocks the world. But the aliens have a hidden motive, one that forces humanity to confront an unworldly terror that threatens their very existence.