Brian, a simple shovel salesman, thinks Alice is the girl of his dreams, but she's the stuff of nightmares: a shape-shifting alien bent on destroying the human race through sheer reproductive power. Brian soon gives birth to a half-human infant, the first of an alien master race. With the help of a psychotic private detective and an archaeologist with a mysterious past, Brian races to save the world from certain destruction. But as the bond between mother and child grows, will Brian be capable of making the ultimate sacrifice to save his species?