“All Her Fault” Ending Explained: What Happened to Carrie and Milo?

Was it All Her Fault after all?

That’s the question fans have been asking since Peacock’s thriller miniseries starring Sarah Snook and Dakota Fanning premiered on Nov. 6. Adapted from author Andrea Mara’s 2021 novel of the same name, the show follows affluent mom Marissa Irvine (Snook), who arrives to collect her 5-year-old son, Milo (Duke McCloud), from a playdate only to find that he was never there.

As the family’s frantic search begins, the media is quick to point the finger at Marissa and her friend, Jenny Kaminski (Fanning), whose nanny, Carrie Finch (Sophia Lillis), becomes the prime suspect. What starts as a desperate hunt for a missing child unravels into a complex portrait of motherhood, privilege, blame and how far one will go to protect their family.

The starring actresses described their characters as “extremely resilient” women in a November 2025 clip shared with PEOPLE.

“Following the female characters of the story, like what their responsibilities are, in terms of the balance of that with their male counterparts… dentist, pick up the dry cleaning, there’s still the to-do list running for their household chores,” Snook said. “When those responsibilities are not fulfilled, it’s easier to say, ‘It’s all her fault.’ ”

So, how does All Her Fault end? Here’s everything to know about the final episode of the limited series and the real explanation behind Milo’s disappearance.

Warning: All Her Fault spoilers ahead.

How does All Her Fault end?

Milo’s sudden and unexpected return leaves Marissa shaken, especially considering that the police are no closer to locating Carrie, even after she murdered two men.

Her world unravels further when she learns that her colleague and longtime friend Colin Dobbs (Jay Ellis) has not only been stealing money from her firm to pay off his gambling debts, but that it was his bookie that police found dead in Carrie’s motel room. Desperate to know if he was involved in her son’s abduction, Marissa and her husband, Peter Irvine (Jake Lacy), confront Colin at their home.

While the family — including Peter’s brother Brian (Daniel Monks) and sister Lia (Abby Elliott) — is in the midst of an explosive argument, Carrie walks into their living room, holding a gun.

Why did Carrie kidnap Milo?

The second-to-last episode of All Her Fault chronicles Carrie’s growing obsession with Milo and how she pulled off the abduction with the help of her felon boyfriend, Kyle Smit (Dominic Masterson), and her bookie dad, Rob Murphy (Erroll Shand).

Though Carrie, whose real name is Josephine Murphy, is painted as mentally unstable from the fallout of losing her own newborn child when she was 16, she reveals to Marissa in the final episode that her obsession with Milo isn’t random. She believes he’s her real son.

What happens to Carrie? 

After accidentally shooting and killing Colin in a struggle for the gun, Carrie exclaims that she doesn’t want to hurt anyone, and didn’t come to take back Milo. She only wanted to warn Marissa about her husband, Peter.

The series reveals that Carrie, Marissa and Peter were involved in a devastating car accident six years prior that resulted in the death of Carrie’s newborn baby. Marissa thought that the mom had died by suicide after the wreck. But now, Carrie claims that not only is she Josephine but that it was Marissa’s baby who died that night, not her own.

She alleged that Peter, who was the only one conscious after the wreck, switched their newborns after realizing that theirs was no longer alive. Peter then kills Carrie with the gun, claiming self-defense even though she begged for her life.

Who is Milo’s mom? 

The final scenes of the limited series reveal that Carrie is Milo’s biological mother. Before the police arrive, Peter admits to Marissa that he switched the newborns after the accident, and said he did so because he thought Carrie was dead.

Detective Alcaras (Michael Peña) — who had been investigating Milo’s kidnapping from the beginning — comes to the same conclusion after he realizes that both Carrie and Milo have synesthesia, a neurological condition where sensory crossovers occur, like tasting colors.

Though he has his suspicions that Peter killed Carrie on purpose, there isn’t enough evidence to prove it.

What happens to Peter?

Even though Marissa witnessed Peter kill Carrie and later learned that he also killed her father after he threatened to reveal Milo’s real identity, he convinces her not to go to the police. She fears that giving them that information would result in Milo being taken away.

Weeks later, at Colin’s funeral, Peter suffers a severe allergic reaction to soy after kissing Marissa, who says she accidentally ate something without checking the label — a step she never skips. To make matters worse, the EpiPen in his jacket has expired, and the emergency kit they always keep in the car is mysteriously missing.

Though Lia calls an ambulance, it arrives too late and Peter dies, realizing in his final moments that his wife poisoned him on purpose.

What happened to Marissa?

As Peter takes his final breaths, the limited series jumps back in time to show Marissa secretly removing the emergency kit from their car and pulling an expired EpiPen out of their home’s disposal box. She replaces the active device in his jacket pocket with the dud, rendering him without any aid should an allergy attack occur.

All Her Fault concludes with Detective Alcaras telling Marissa that he knows what Peter did and feels “fine” not investigating Peter’s death any further.

The limited series ends with Marissa and Jenny watching their boys have a playdate. While the kids run around with bubbles, the moms sip glasses of wine and smile at each other — knowing that they’re finally safe.