June and her husband Jack are in a car accident. Jack dies, policeman Kurt helps June and eventually they marry and prepare for birth of a daughter. During the building of an addition to their house their contractor leaves, leaving them with a hole in a wall and rain leaking through the attic ceiling. Shay Bourne arrives one day and is hired to work. One day after June's eighth month ultrasound she arrives home to find Kurt and Elizabeth shot. Shay is charged with their murders.
The jury convicts Shay of two counts of capital murder. The jury then deliberate on the death penalty. Eventually they all agree with Michael being the last juror to agree on the death penalty.
Shay Bourne is transferred to the I-tier at the Concord state prison. Shay is in the cell next to Lucius DuFresne an artist with HIV who killed his gay lover. During the night Shay tells Lucius the he wants to donate his heart to a little girl that he saw on TV.
Michael the juror has become the junior priest at a parish in Concord, New Hampshire.
June has long since given birth to her daughter Claire, who is in the hospital awaiting a heart transplant. Although she has had an defibrillator transplanted in her heart prior, it is wearing her out and without a new heart, she is sure to die.
Back in the I-tier there is a strange incident with wine flowing through the toilet pipes. Shay's final appeal is denied and his execution date is set, two and a half months away. He fights with Maggie, his lawyer, for the right to be hanged instead of lethal injection because he wants to give Claire, the little girl, his heart.
Calloway is covertly caring for a bird (Batman the Robin) in his cell. He plays a game of chess with Shay where the stakes are Shay's brownie and Calloway's bird. Guards come in and search Calloway's cell and the bird is tossed across the cell and killed. Shay still wants his winnings and after the dead bird is given to Shay (in his cell out of sight) the bird comes back to life.
Claire is in the hospital as she has been told that they have a heart available for transplant. But the heart had a bad right ventricle. Michael while saying Mass drops a consecrated host into the wine and sees a vision of himself on the host.
Back in the I-tier Shay gives gum to all the men on the ward even though he says he has only one piece. When Lucius chews it the sores in his mouth no longer hurts, he sleeps through the night for the first time in 6 months and when he wakes his AIDS appears to be gone. The news makes it to the media and people and news crews come to the state prison, many believing that Shay is the Messiah.
Michael visits Shay in prison and Shay tells him the he specifically wants to donate his heart to Claire. Maggie arrives and becomes Shay's lawyer. Maggie finds that in the New Hampshire death penalty code it states that an inmate can be hanged if the commissioner finds it impractical to carry out the sentence of death by lethal injection. Michael investigates the supposed miracles and finds that Lucuis' irreparable damage to his brain caused by the HIV has been reversed.
June agrees to meet Shay in a restorative justice meeting. In the meeting June asks Shay "Why did you do it?" Shay responds "She was better off dead." June does agree to take Shay's heart out of spite. Maggie starts the legal process to petition commissioner of corrections to allow Shay to be hanged so his heart can be donated to Claire. Shay is determined by Clare's doctor to be a perfect heart transplant match. Maggie brings Father Michael to her parents house for dinner and during a religious discussion Rabbi Bloom gives Father Michael a book about the Gnostic Gospel of Thomas written by Ian Fletcher. Shay has quoted various parts of the Gospel of Thomas. One of the prisoners in the I-tier attacks a guard guard with a broken broom handle while cleaning his cell. He is pronounced dead by the EMT's, Shay is seen huddled in the corner of his cell apparently praying and the dead guard comes back to life while the EMT's are moving his body. Another prisoner using the confusion attempts to kill Shay.
Father Michael visits Ian Fletcher to discuss the Gnostic Gospels. Maggie arranges a dinner meeting with Dr. Gallagher to discuss organ donation for Shay. The dinner turns into a date. June sneaks Dudley into the hospital to make Claire feel better and a nurse reveals the upcoming transplant which June has not discussed yet with Claire. Shay's trail begins, Michael testifies that its his religious belief that he needs to donate his heart to Clarie to obtain redemption. Father Michael uses Shay's quotations from the Gnostic gospels as his religious foundation. Ian Fletcher then testifies as an expert on the gnostic Gospels. Father Michael admits to Shay that he was on the jury that convicted him. Mather Michael locates Shay's sister, Grace and tried to convince her to forgive Shay for setting the fire that disfigured her face. While testifying at his trial all of Shay's chains fall away from him for no apparent reason.
Shay tells Father Michael that on the night of the murder that Shay had came into the house and Kurt, Elizabeth's stepfather was molesting her and that during a struggle with a gun and both Kurt and Elizabeth were killed. Shay refuses to allow Maggie to use that information to try and delay his execution. Claire convinces her mother to let her die and June tells Maggie that she is refusing Shay's heart. Lucius dies in the prison from AIDS-related pneumonia. Maggie and Christian make love and spend the night together. Judge Haig hands down his ruling and instructs the state to allow Shay to be executed by hanging so his heart can be given to Claire. Shay's sister Grace visits June and tells the story of how she was abused by her foster father, how she set the fire which kills him and which Shay takes the blame. She plants the idea in June's mind that Kurt might have been abusing Elizabeth and June changes her mind and accepts Shay's heart. Just before his execution Shay admits for Father Michael that he did murder Kurt after the struggle with the gun where Elizabeth was accidentally killed. Shay's heart is successfully transplanted into Claire. Three days after Shay's execution his sister gives Father Michael Shay's things from his prison cell, in it was a page torn from The Gospel of Thomas.
Publishers Weekly in their review said that "Picoult bangs out another ripped-from-the-zeitgeist winner. Picoult moves the story along with lively debates about prisoner rights and religion, while plumbing the depths of mother-daughter relationships and examining the literal and metaphorical meanings of having heart." It also says that "The point-of-view switches are abrupt, but this is a small flaw in an impressive book", however, others say that the different viewpoints of the characters provide valuable insight to the story for the reader and abruptness is inevitable.
Donna Seaman reviewing in Booklist says that it is a "a compulsively readable saga and dramatic critique of capital punishment". She compares Change of Heart to The DaVinci Code by Dan Brown. And that the novel is "Laced with intriguing musings on the Gnostic Gospels, Picoult’s bold story of loss, justice, redemption, and faith reminds us how tragically truth can be concealed and denied.
Janet Maslin writing for the New York Times had several complaints about this novel. She felt that Jodi Picoult wrote the novel on "authorial autopilot", that it has the subtlety of a jackhammer and was made needlessly long by scenes such as Maggie chatting with her pet rabbit. She says that June Nealon is "a wet hankie of a character, full of grief and anger, but otherwise lacking any distinguishing characteristics." She felt that Jodi Picoult missed her own chance at redemption, "had Change of Heart culminated in revelations that were truly plausible or unexpected, its vapidity might have been transcended. But there is no substance to the story’s last surprises."
In terms of public reception, Change of Heart debuted as number one on the New York Times Fiction bestseller list. It remained at the number one position for two additional weeks, before being knocked from the number one position on April 13, 2008 by Jonathan Kellerman’s Compulsion.