In this sequel to "Rich Man, Poor Man," moviemaker Gretchen Jordache, the until-now unseen sister, strives to pull the family together after the murder of brother Tom and the disappearance of brother Rudy by first reestablishing contact with her soldier son, and then patching things up with her sister-in-law, Kate, Tom's widow.
Inspectors for the U.S. Public Health Service try to track down the cause of a rash of mysterious ailments suddenly appearing among the general populace.
David, a college student, is looking for a job. He is hired by Dr. Stoner as a lab assistant for his research and experiments on snakes. David also begins to fall for Stoner's young daughter, Kristina. However, the good doctor has secretly brewed up a serum that can transform any man into a King Cobra snake-and he plans to use it on David.
Private investigator Leo Gordon is hired to trail Karen Mendaros, the mistress of a reclusive billionaire. When they meet, Gordon and Mendaros hit it off and check in at a motel. Gordon wakes up the next morning and discovers that Mendaros had been murdered during the night. Gordon opens his own investigation of Mendaros' past in an attempt to determine who killed Mendaros and why he's been set up as the fall guy.
When a saboteur places an explosive device on a train full of sea mines, the authorities call for bomb expert Peter Lyncort to diffuse the situation, unaware that he has explosive problems of his own.
