Life Expectancy opens, appropriately, with the birth of Jimmy Tock. In another room of the same hospital, just before, his grandfather is dying, but not before making dire predictions about Jimmy. Having just had a stroke days earlier, it’s a wonder he can say a single word, much less predict the time of Jimmy’s birth, his size and weight, and the fact that he would have fused toes on each foot. He includes with his predictions five terrible days that Jimmy will have to watch out for. He warns Jimmy’s father Rudy that they should watch out for the clown. The clown in question is Konrad Beezo, whose wife has just died in childbirth, an excuse he uses to go on a murderous rampage in the hospital. Jimmy grows up with the knowledge that the first day will take place when he is twenty years old. On that day, Jimmy runs his errands as usual, and ends up at the library. He isn’t there five minutes before the librarian, Lionel Davis, is shot to death.
The maniac shooter takes Jimmy hostage along with Lorrie Hicks, the woman who will eventually be Jimmy’s wife. The maniac is joined by two accomplices before he finally announces his true identity: Punchinello Beezo, son of Konrad and Natalie and the grandson of Virgilio Vivacementes, who had not approved of Konrad as his son-in-law. According to Punchinello, his dislike for his son-in-law led Virgilio to hire a hitman to kill all of them on the night of Punchinello and Jimmy’s births, thus resulting in the massacre. Punchinello and his crew blow up a significant portion of the town. Fortunately, Lorrie escapes unscathed and Jimmy with injuries from which he recovers.
Three years later the second day is due to take place, but not before Lorrie gives birth to their first child. On the way to the hospital, they are attacked by Konrad Beezo, who wants to steal the baby. Eventually they escape and leave him shackled to a tree, but he disappears by the time the police arrive. The second prediction follows, where Konrad burns their house down with a note that he will come back if they ever have a boy. They do, and his name is Andy. The third and fourth days bring more tragedy – Konrad Beezo returns to shoot Lorrie, and Annie needs a kidney transplant. This leads to the realization that Punchinello is Jimmy’s fraternal twin and Jimmy was switched at birth with Rudy Tock’s stillborn infant. Punchinello expects a few favors in order to comply with the request, but he does and Annie lives.
The fifth day begins with a gift – fifty thousand dollars from Virgilio Vivacemente – in exchange for their son, Andy. Virgilio impregnated his own daughter, Natalie, and the result was Jimmy and Punchinello. Virgilio wants to train Andy to become an aerialist. The Tocks turn him down, and Virgilio shoots Jimmy in anger. Lorrie came prepared and shoots Virgilio in retaliation. This ends the five terrible days.
The first half of the book revolves around the first terrible day with Jimmy and Lorrie at the library, which culminates in an explosion. The next three days include subsequent attacks by Punchinello’s father Konrad Beezo which cause the family great injury but no deaths. The last day is intended to be either Jimmy or Lorrie’s death, but both survive and the Beezo curse is then eradicated. Koontz ends his story with a trick. Jimmy’s last child, Rowena, is born and a pronouncement is made from another patient that is similar to the one made by Jimmy’s grandfather. This time, a prediction is made for the child’s five wonderful days in the future.
