Near the western border of Kansas, among wheat fields and dusty roads, lies Holcomb, a small community of farmers and ranchers. On the morning of November 14, 1959, Herb Clutter strolls across the grounds of River Valley Farm, heading toward a grove of trees that he nursed to life with the same care and purpose that he used to raise four children and build one of the largest, most prosperous spreads in Finney County. An educated, widely respected wheat farmer, Herb Clutter has little to worry about that Saturday morning. A lingering illness left his wife, Bonnie, partially disabled, but recent medical tests encourage the family to think that her medical problem is improving. Daughter Nancy, sixteen years old, the town sweetheart, helps with the household chores. She and her brother, Kenyon, fifteen years old, are outstanding students in the local high school. Two older daughters live out of town.

On that same morning, nearly four hundred miles east, in Olathe, Kansas, Perry Smith sits in a café waiting for his friend, Dick Hickock. They plan to drive to Holcomb, rob Clutter, kill everyone in the house, and flee to Mexico, where they hope to buy a boat and hunt for undersea treasure. Recently paroled from Kansas State Penitentiary and ordered to stay out of the state, Perry is persuaded to return to Kansas when Dick, also paroled, writes him of his plan to rob Clutter. According to Dick’s last cellmate, a former hired hand of Clutter, the farmer keeps as much as ten thousand dollars in his house.

Arriving at the Clutter farm near midnight, Perry and Dick enter through an unlocked door, awaken the victims, tie them up, and put them in separate rooms in the house. The killers find no wall safe stuffed with thousands of dollars; instead, they find Clutter’s wallet, containing about forty dollars. Still determined to leave no witnesses, the killers cut Clutter’s throat, then shoot him in the head at close range with a shotgun; the other three victims are shot, one by one, in similar fashion.

When the bodies are discovered the next morning, neighbors, friends, and relatives are electrified by the shocking crime. Alvin Dewey and his team of three investigators from the Kansas Bureau of Investigation in nearby Garden City interview anyone remotely connected to the Clutters or to River Valley Farm. Nothing develops from these efforts, not even a firm theory as to whether the Clutters were killed by one person or by two, and none of the investigators is sure why the four were killed. Robbery is a possible motive, but the few clues left by the killers confirm none of these theories.

Back in Olathe, Perry and Dick continue with their plans to go to Mexico, despite their failure in Holcomb. On November 21, Dick begins passing bad checks to finance their Mexican venture. Mexico, however, proves grimly disappointing. After a week in Mexico City and a trip to Acapulco, they use up most of their money, and the pawned merchandise is all but gone as well. A wealthy German finances a few days on a fishing boat, but plans of diving for treasure are scuttled by the obvious: Neither man takes well to water, and money is as elusive as the buried treasure of Perry’s dream. Back in Mexico City, their car sold and their finances rapidly dwindling, they decide to return to the United States. A bus takes them to Barstow, California, where they set about hitchhiking toward Kansas, harboring a plan to rob and kill a motorist. That plan is foiled when the prospective victim, a salesman who gave them a ride, stops for another hitchhiker.

Dewey’s investigation takes an upward turn when Hickock’s former prison cellmate tells the warden of Hickock’s plan to rob and kill the Clutters. That lead proves promising. The agents begin hunting Smith and Hickock, but the killers elude capture as they drive through Kansas in a stolen car. They pass bad checks to finance a trip to Miami, where they spend Christmas. Once again without money, they turn toward home, redeeming empty bottles found along the highway. Their journey ends in Las Vegas with their arrest in front of the post office; they stopped to pick up the package containing the boots worn during the Clutter murders. Perry mailed the package from Mexico. Dewey and his team hurry to Las Vegas, where, under the pressure of interrogation, Dick confesses to the crime. On the car ride back to Garden City, Perry recounts the details of the crime in full.

Housed in the county jail, the pair spends three months awaiting trial. The prosecution has a strong case, based on the murder weapons, the boots worn by the killers during the murders, the testimony of Dick’s former cellmate, and the killers’ confessions. The defense attorneys have no case. A psychiatric examination fails to justify a plea of insanity, and a few character witnesses do not sway the jury in favor of the two defendants. Both are convicted of all four murders and sentenced to hang.

Sent to the state penitentiary in Lansing in April, 1960, Perry and Dick spend the next five years on Death Row. Through a narrow window they can see across an empty lot the door that leads to the gallows. Three execution dates come and go, and when their last appeal is denied, they are hanged on April 14, 1965.