On August 4, 1892, Bridget Sullivan, the maid, summons neighbor Mrs. Churchill to the Borden residence, where Lizzie Borden meets her at the door coldly stating, “Mrs. Churchill, do come in, someone has killed father.” Andrew Borden’s body reclines on the living room sofa with multiple hatchet wounds across his face. Police arrive to examine Andrew’s body, and upon searching the house, Mrs. Churchill and Bridget find the body of Abby Borden, Lizzie’s stepmother, hacked to death in the guest room.
Neighbors flock to surround the house. Emma Borden, 9 years older than 31-year-old Lizzie, returns from Fairhaven, where she was away staying with friends. Emma directly asks Lizzie if she killed father, which Lizzie denies. Lizzie is given morphine to sedate her and answers police questions inconsistently.
At the funeral Lizzie is criticized for not wearing black or showing grief. Lizzie is informed that she is a suspect, and an inquest is held.
At the inquest Bridget says she and Lizzie were the only ones in the house, besides the victims, the day of the murder. Mr. Borden left for downtown, and Mrs. Borden received a note—that nobody ever saw—asking Abby to care for an unnamed sick friend. As instructed by Mrs. Borden, Bridget was outside the house, with the doors locked, washing windows at the time of the murders. Bridget didn’t see anyone come to the house until Mr. Borden came home at about 10:45 and took a nap on the sofa. Bridget lay down for a nap as the city hall clock struck 11 o’clock, but 3 or 4 minutes later Lizzie called out after discovering Andrew’s body.Lizzie testifies that she called her stepmother Abby “mother” when she was a child but began to call her “Mrs. Borden” later, without explaining why. Lizzie changed her story several times, unsure whether she was upstairs or downstairs when her father came home. She claimed to have last seen Abby 1 hour and 30 minutes before her body was discovered. Nobody saw the note to Abby or saw her return home. Andrew was in the house 15 to 20 minutes while Lizzie was in the barn looking for an iron sinker for her fishing line for a trip the following Monday. Lizzie cannot explain how someone unknown killed Abby an hour and half before, while both Bridget and Lizzie were around, then killed Andrew during the 20 minutes or so that she was in the barn and Bridget was preparing to nap. The magistrate judges Lizzie probably guilty and orders Lizzie committed to await trial.
Lizzie faces death by hanging. With Emma’s support and her share of her father’s $250,000 estate, Lizzie retains a “dream team,” headed by George Robinson, former governor of Massachusetts. She decorates her prison cell with furniture and selects a special wardrobe for the trial. The press and public are sympathetic to Lizzie, a Sunday school teacher and a devoted worker for temperance, Christian aid, and foreign missions.
Lizzie’s testimony at the inquest is deemed inadmissible, as she was denied proper counsel and her testimony was taken when she was under the influence of morphine.
At the trial, friend Alice Russell testifies that the evening before the murder Lizzie said her father was having trouble with business associates, was afraid someone would harm him, and the house had been broken into in broad daylight when family members were at home. The day after the funeral, Lizzie burned a dress in the stove that supposedly was stained by paint.
The local chemist testifies that Lizzie attempted to purchase prussic acid a few days before the murders, ostensibly to clean a sealskin cape. He would not sell her the poison without a prescription.
A forensic expert testifies that the broken hatchet found by police matches wounds on Mr. Borden’s skull. The assailant’s clothing would be splattered in blood, yet Lizzie had no bloodstains on her just moments after the last murder, except for a small amount of menstrual blood on her clothes. When Andrew’s and Abby’s skulls are produced in court and a hatchet is fit into the wound, Lizzie faints.
The foreman of the all-male jury is asked to announce the verdict. In flashbacks, Lizzie recalls the sequence of events leading up to the murder. Abby persuades Andrew to change his will, and Andrew agrees to see his lawyer next week. Lizzie says to Emma that she would see Abby dead first and that her father must not make a new will. Emma decides to go to Fairhaven the next day. Lizzie then flashes to Bridget washing windows then chatting with a neighbor. Locking the doors, Lizzie strips off her clothes, taking a hatchet from under her mattress. Nude, Lizzie sneaks up behind Abby and Andrew in turn, hacking each to death. Between both murders, Lizzie washes up in the basement and dresses again in unsullied clothes. She dumps the hatchet in the latrine. The foreman announces a “not guilty” verdict. Lizzie is ordered released. The crowd outside the courtroom celebrates.
At home, Emma welcomes Lizzie doubtfully, asking her, “once more, then I shall never mention it again as long as I live. Did you kill father?” Lizzie’s face remains expressionless, and she does not respond.
Months after her acquittal Lizzie moved into a mansion in the fashionable section of Fall River, where she lived until she died in 1927, at the age of 66. Emma died nine days after Lizzie. To this day the case remains unsolved.
Lizzie Borden is put on trial for the murders of her father and stepmother, facing the possibility of death by hanging. She secures a strong legal defense and her testimony at the inquest is ruled inadmissible, impacting the trial's outcome.
The film concludes with the legal system struggling to convict Lizzie due to lack of physical evidence and procedural errors regarding her testimony. The ambiguity over her guilt remains unresolved, leaving viewers to ponder whether justice was served or if the truth was buried along with the Bordens. The ending underscores the case's status as a haunting, open question in American true crime lore.