The Doomsday Conspiracy is a hybrid piece of writing that employs the methods of romance, mystery, and science fiction stories. An ideal couple at the outset of their love affair, Robert Bellamy and Susan Ward enter a marriage which ends in divorce because his frequent absences and the secrecy and dangers of his work cause tensions that she cannot endure. Sheldon must arrange his plot so that despite her second marriage this pair can be reunited.

Certain elements of the standard soap opera can be seen here.

A tour bus has stopped where the UFO, apparently a kind of shuttle craft, has crashed. Bellamy on what he is determined to make his last assignment, has been ordered to find all of the passengers who were on the tour that day and report their names and addresses to General Mark Hilliard.

Each tourist meets what is made to appear...