Turk is 11 when his brother Tanner is killed in a car crash. After the other driver involved in the accident, a Black man, is acquitted, Turk's family falls apart: his parents separate, and Turk's mother begins drinking excessively. Turk, angry and resentful about Tanner's death, is drawn into the white supremacy movement. A white power leader named Francis Mitchum reaches out to him, and he falls in love with Francis's daughter, Brit. They get married two years later and have a son, Davis, at the Mercy-West Haven hospital.
Meanwhile, Ruth is the only Black labor and delivery nurse at Mercy-West Haven. She was raised by a single mother, Mama, who was a domestic servant for a wealthy white family. As an adult, Ruth feels like she's a respected member of her mostly white community. One October morning, Ruth is assigned to care for Brit and Davis. She performs the newborn exam, but Turk demands that not be allowed to touch his son, which angers Ruth. The next morning, Davis's nurse asks Ruth to watch him. Davis stops breathing, so Ruth tries to help him—but Ruth isn't supposed to touch him per Turk's request, so she stops herself. Just then, the charge nurse arrives, and a team tries to revive Davis. Ruth performs CPR, but Davis dies.
Two weeks later, Turk files a complaint against Ruth, claiming that she killed Davis. The state of Connecticut takes away Ruth's nursing license, and she's arrested. At Ruth's arraignment hearing the next day, her public defender is Kennedy McQuarrie. During the hearing, Turk sits in the gallery and spits on Ruth's face. Ruth goes to jail, though her teenage son Edison is able to bail her out that night. A couple of days later, Kennedy convinces her boss to let her take Ruth's case.
Near the end of January, Ruth is having dinner at Kennedy's house when she gets a phone call with the news that Mama had a stroke and died. Days later, at the funeral, Ruth realizes that Mama tried to make Ruth understand that the Black church community would always be there for her. At the lunch afterwards, Kennedy and her mother, Ava, offer their condolences. Ava, who was raised in the South by a Black nanny, tells Ruth that Mama didn't waste her life and shows Ruth a photograph of herself and her own maid, Beattie.
As Ruth's court date approaches, Kennedy learns that Ruth's case will be tried by Judge Thunder, an irritable judge who doesn't like Kennedy. Howard, a young lawyer in the office, is able to weed out potentially racist jurors during the selection process. That weekend, Kennedy meets with Ivan Kelly-Garcia, a neonatologist. He looks through Davis's lab results and notices that Davis has MCADD, a condition that could have killed him if his blood sugar dropped.
On the first day of the trial, the prosecutor Odette's opening statement casts Turk's request that Ruth not touch Davis as a personal preference. Kennedy insists that Davis had a medical condition and may have died regardless of who cared for him or what treatment he received. After lunch, several doctors, including the pediatrician, Dr. Atkins, testify. Dr. Atikins reviews Davis's newborn screening, telling the court that the results suggest nobody could've saved him.
The medical examiner, Dr. Binnie, testifies the next morning. She says that the bruises on Davis's body could've been the result of medically necessary CPR, and that Davis was already at risk because of MCADD. Then, Turk testifies and ends up screaming and cursing at Kennedy. Kennedy sees this as a win, and during a meeting with Judge Thunder and Odette, Judge Thunder agrees to throw out the murder charge against Ruth and consider her movement for acquittal. Ruth, however, still insists on testifying and tells Kennedy that she lied: she did actually touch Davis. But Kennedy knows that if Ruth speaks, they'll lose.
The next morning, Ruth testifies and tells the truth. Odette yells at Ruth, working her up, and Ruth snaps and says that Davis was better off dead than raised by Turk. Though Kennedy is upset, Ruth feels like she's finally had the chance to speak, and she fires Kennedy . When Kennedy gets home, she decides to walk through a poor Black neighborhood to feel how Ruth feels. She thinks that if she were braver, she'd bring up race in the courtroom and do her part to fix the system. That night, unable to sleep, Kennedy looks over Davis's screening results again and notices that he was a carrier for sickle cell anemia. She contacts Black television personality Wallace Mercy and has him look for Brit's birth certificate.
That Monday, during closing arguments, Kennedy speaks about how racism is largely invisible to white people. Odette maintains her stance that Ruth didn't do her job. As everyone leaves the courtroom, Wallace Mercy and a Black woman approach Turk and Brit. The woman says that she's Brit's mother. Turk is flabbergasted and looks to Francis, who looks shocked and calls the woman Adele. Brit runs off. As Turk and Francis look for her, Francis explains that he and Adele were in love, but she left him. Francis became a white supremacist after this, and he never told anyone that Adele was Black. Francis and Turk eventually find Brit at Davis's grave, cutting her arms in an attempt to get her mother's blood out of her body. They take her to a hospital, and Turk tries to reconcile his racism with his love for his wife and son, who he now knows were part Black.
Two days later, the jury is split on their verdict. The next morning, Judge Thunder tells Kennedy and Odette that it's a hung jury, 11 to one. Back in the courtroom, Judge Thunder dismisses the jury and rules in favor of Ruth's motion of acquittal. She's free to go.
Six years later, Turk is at the doctor's office with his daughter, Carys. He explains that Brit committed suicide as he was filing for divorce, and since then, he's reformed his views and remarried a woman named Deborah. He now speaks about his experiences for the Anti-Defamation League. When the nurse comes in, Turk recognizes her as Ruth. She diagnoses Carys's strep throat, and as she leaves the room, Turk thanks her. He can't tell if she recognizes him or not.