The final episode of Peacock’s thriller All Her Fault delivers one dramatic twist after another, answering the mystery of Milo’s kidnapping while revealing a six-year-old secret that changes everything. What begins as a story about a missing child transforms into a deeper story about truth, control, and the impossible choices mothers face.
The series ends with a tragic confrontation at the Irvine family home, the true identity of the nanny Carrie, and a calculated act of justice that leaves viewers questioning everything they thought they knew about the characters.
The Final Confrontation: What Happens to Carrie?
In the climax of the series, Carrie Finch, played by Sophia Lillis, arrives at the Irvine home with a gun. Marissa Irvine (Sarah Snook) and her husband Peter (Jake Lacy) are in a state of high tension following the return of their son, Milo. Carrie is not there to take the boy again. Instead, she has come to reveal her true identity and warn Marissa about the man she married.
Carrie reveals she is actually Josephine “Josie” Murphy. She attempts to play an audio recording from a cell phone that contains proof of Peter’s crimes. Before she can share this evidence, a struggle ensues. Peter tackles her, and in the fight, Carrie is shot and killed with her own weapon.
“I never wanted to hurt anyone,” she sobs after an accidental shot from the struggle kills Colin Dobbs, Marissa’s friend and colleague.
“I didn’t come to take Milo… I came for a promise. Mother to mother. That you’ll protect him,” Carrie tells Marissa, staring directly at Peter. “You don’t know what he’s capable of”.
Peter claims the shooting was an act of self-defense, but Marissa immediately senses he is hiding something much larger. Carrie’s death is the tragic conclusion to her quest for the truth about her son, but her actions successfully expose Peter’s web of lies.
The Shocking Motive: Why Carrie Really Kidnapped Milo
The central mystery of All Her Fault is not who took Milo, but why. The answer reframes the entire story. Carrie kidnapped Milo because she believed, correctly, that he was her biological son.
Six years before the present-day events, Marissa and Carrie were both involved in a catastrophic car accident just after leaving the hospital with their newborn babies. Marissa was left unconscious. In the wreckage, Peter discovered that their own infant son had died. Believing that Carrie (Josephine) was also dead, he made a fateful and horrifying decision: he switched the babies, taking Carrie’s living child and placing their deceased son with her.
Marissa awoke from the accident believing her baby had survived, while Carrie was told her child had died. Carrie spent years grieving, until a chance encounter made her suspect the truth. This led her to create a fake identity to get a job as a nanny for Jenny Kaminski (Dakota Fanning), who was friends with Marissa, so she could get close to Milo.
The series provides a crucial biological clue that confirms their connection. Both Carrie and Milo experience synesthesia, a rare neurological condition where senses are blended, such as tasting words or seeing colors for sounds. Detective Alcaras (Michael Peña) learns this condition is often inherited, which supports the truth that Milo is Carrie’s son.
Peter Irvine’s Web of Lies and Control
Carrie’s kidnapping plot exposes the dark reality of Peter Irvine’s character. He is not the supportive husband he appears to be, but a man who builds his life on controlling the people around him through deception.
- The Original Crime: The baby switch after the car accident was the first major lie, which he justified as “protecting” Marissa from grief.
- A Pattern of Manipulation: It is revealed that Peter caused the childhood accident that left his younger brother, Brian, disabled. He then allowed his sister, Lia, to believe it was her fault, binding them both to him through guilt and dependency for years.
- Further Violence: After Milo is kidnapped, Peter meets Carrie’s father, Rob, for a ransom exchange. While Rob’s back is turned, Peter kills him with a lamp to silence him. He then stages Milo’s “return” by leaving him near a police station.
Peter’s need to control his narrative and his family ultimately leads him to kill Carrie to prevent her from exposing his original crime. For Marissa, hearing the recording of Peter killing Rob and his confession about the baby switch reveals she is married to a murderer and a master manipulator.
Marissa’s Impossible Choice and Final Act
Faced with the truth, Marissa is trapped. If she goes to the police, she risks losing Milo, as he would likely be taken into the system following the death of his biological mother. She is also terrified of what Peter might do if confronted by the law. Carrie’s dying wish was for Marissa to protect Milo.
Marissa makes a calculated decision. Knowing Peter has a severe soy allergy, she orchestrates a fatal encounter. At the funeral wake for Colin Dobbs, she deliberately eats soy, kisses Peter, and triggers a violent allergic reaction. She has secretly removed the emergency epinephrine kits from their home and car, and swapped the EpiPen in his jacket for an expired one.
As Peter dies, understanding flashes across his face. “It’s true. I manage your allergies for you,” Marissa tells him softly.
Sarah Snook, who plays Marissa, reflected on the complexity of the moment: “It’s definitely a moment of justice. It’s a moment of sadness… because in this moment I’m taking away my son’s father and I want my son to have the memory of a father who was good”.
This act is portrayed not as simple revenge, but as the only escape she can engineer to protect her son from a controlling and dangerous man.
The Aftermath: Truth, Silence, and a Fragile Peace
In the aftermath, Detective Alcaras pieces together the full story. He understands the connection of synesthesia between Carrie and Milo, and he deduces Peter’s crimes and likely what Marissa has done. However, he chooses to close the case quietly.
When his partner expresses suspicion about Peter’s death, Alcaras shrugs it off. He later speaks with Marissa, telling her he knows what Peter did and that he is “fine” with the case being closed. This represents a moral choice that true justice sometimes exists outside the legal system.
The series ends with a quiet scene of Marissa and Jenny watching their sons play. It is a moment of fragile peace, not a perfectly happy ending. These women are free from the immediate threats, but they carry the weight of terrible secrets and actions taken for the sake of their children.
Also Read: South Park Season 28 Finale Recap: The Trump-Satan Baby Plot Ends With a Dark Twist
