In 1963 Los Angeles, California, police officer Karl Hettinger transfers to the felony squad and finds his new partner, Ian Campbell, practicing the bagpipes in the precinct basement. While on patrol, the two officers get to know each other and discover a common background as college dropouts and Marines. Elsewhere in the city, Jimmy “Youngblood” Smith is paroled after five years in prison for burglary. An acquaintance named Billy introduces him to Gregory Powell, a brash and charismatic ex-convict who invites Smith to participate in his moneymaking schemes. Although leery of getting involved with the miscreant, who has a volatile temper, Smith needs money and agrees to be the driver for a holdup at a liquor store, where Powell steals $300. Afterwards, Powell shuns the alcoholic Billy in favor of Smith, a youthful and more reliable partner in crime. During a gambling trip to Las Vegas, Nevada, with Smith, Powell purchases a new car and guns. Staying at motel in Bakersfield, California, Powell suddenly decides that he and Smith must return to Los Angeles for another heist. Smith is reluctant, but feels too intimidated by Powell to defy him. Back in the city, Powell makes a U-turn on a side street. Officers Ian and Karl notice the suspicious-looking duo, who are dressed in matching black leather jackets and hats, and decide to pull them over on a probable cause of no brake lights. When Ian approaches the vehicle and tells Powell to step out of the car, Powell pulls a gun on the officer. Threatening to shoot Ian, Powell forces Karl to surrender his pistol, then orders the two policemen to get into his car. At gunpoint, Ian is instructed to drive toward Bakersfield, California, as Karl lies in the back seat. Meanwhile, Smith becomes a willing accomplice in the kidnapping. Along the way, Powell indicates that he is going to drop the officers on a side road. Outside Bakersfield, Powell orders Ian to turn off the highway and stop the car along a deserted, dirt road that crosses an onion field. As Ian and Karl get out of the vehicle, Powell mentions a change of plans and asks the officers about the “Little Lindbergh Law,” then, without warning, shoots Ian in the face. While four more shots are fired into his fallen partner, Karl flees. Powell tries to gun Karl down, but the policeman escapes into the darkened field. Running several miles, Karl reaches a farmhouse and summons help. Later that evening, he leads police to the crime scene, where they find Ian’s dead body in a ditch. In the meantime, the two criminals have split up searching for Karl, and Smith uses the opportunity to break free from his manipulative partner and drive away, leaving Powell stranded in the field. Despite an attempt to evade capture by stealing another car, Powell is pulled over by police along the highway and apprehended. During the interrogation, Powell tells Sergeant Pierce Brooks, the lead Los Angeles Police Department (LAPD) investigator, that Smith murdered the officer and provides clues about his accomplice’s whereabouts. When Smith is arrested in Bakersfield, he screams that he is a thief, not a killer. Meanwhile, Karl attends Ian’s funeral and watches his partner’s grieving mother and wife, during a bagpipe salute. Back at the precinct, Karl’s supervising officer asks him to speak at roll call and explain to colleagues what actions he wished he had done differently that might have saved Ian’s life. In the wake of the incident, the LAPD increases officer training in regards to approaching vehicles and suspects. During one session, a veteran of the force defends Karl’s judgment. The LAPD captain, however, overhears the comment and declares that any policeman who surrenders his gun to a criminal is “a coward.” Powell eventually confesses that he shot Ian in the face, but claims Smith fired the last four shots into the dying officer, which Smith denies. Since Karl was busy fleeing, he is unable to verify who was responsible. While questioning Powell, Brooks raises the issue of the “Little Lindbergh Law.” Powell believes the law stipulates that any kidnapping is a capital offense and, therefore, by killing the officers he had nothing to lose. Brooks, however, corrects him that the law applies to kidnapping with ransom. Until the shooting, Powell and Smith had not committed a capital offense. During the trial, Powell acts as his own attorney and is found guilty of shooting Ian first, while Smith is charged with firing the last four shots. The two criminals are sentenced to the death penalty and incarcerated at San Quentin Prison. Sometime later, Karl is transferred to the detective bureau and his wife, Helen, gives birth to their first child, but he is still tormented by the incident and has reccurring headaches. While tracking a thief at a department store, Karl steals a watch and continues to shoplift until he is caught one day and forced to resign from the police force. Meanwhile, the onion field case continues to drag on for several years, and Powell and Smith are eventually granted a retrial. Karl is asked to testify once again, but he appears muddled during questioning. In a sidebar conference, the prosecutor informs the judge that the former officer’s depression and kleptomania have been diagnosed as a manifestation of his overwhelming guilt about the incident. Powell and Smith’s sentences are eventually reduced to life imprisonment. After relying on his wife to support the family and struggling with suicidal thoughts, Karl starts his own landscaping business and is later offered a management job at a commercial nursery. Although the company is located near the onion field in Bakersfield, Karl tells his wife that the work is a promising opportunity. In the meantime, Powell and Smith await parole dates in 1982. After moving, Karl finally begins to find happiness again and tells Helen that he coincidently heard bagpipes on the radio the last time he passed by the onion field.