Is ‘All Her Fault’ a True Story? Breaking Down the Inspiration for Peacock Drama

[WARNING: This post contains MAJOR spoilers from All Her Fault.]

In Peacock’s new thriller All Her Fault, mother Marissa Irvine (Sarah Snook) arrives to pick her son Milo (Duke McCloud) up from a playdate, only to find that he’s nowhere to be found at the address she was given. In fact, the other mother, Jenny (Dakota Fanning), whom she thought she organized the playdate with, doesn’t even live at the home in question.

All Her Fault is based on Andrea Mara’s 2021 novel of the same name and follows Marissa and her husband, Peter Irvine (Jake Lacy), as they frantically try to reunite with their son. But was this all based on real-life events? Scroll down for everything we know.

Is All Her Fault a true story?

No, All Her Fault is not a true story, but Andrea Mara was inspired by a real-life even to write the book that ended up being the source material for the show.

“I went to collect my daughter from a playdate and found myself standing outside an unoccupied house,” Mara explained in a 2021 YouTube video. “The panic only lasted for a few seconds until a neighbor told me the family had moved houses a few weeks earlier and i was working off an old address list. It all ended very quickly, much more quickly than it does for Marissa in the book.”

In an essay for The Irish Independent, Mara explained what was going through her mind during the few minutes she didn’t know where her daughter was. “Was this some kind of elaborate kidnap plan, whereby they’d inserted their (fake?) daughter into my daughter’s class for the last six months, in a long-game bid to kidnap her?” she wondered. And so the idea for the book, and subsequently, the show, was born.

Who kidnapped Milo in All Her Fault?

In the end, it turned out that Jenny’s nanny Carrie (Sophia Lillis), who used to be known as Josephine Murphy, was the kidnapper. She began speculating that Milo was actually her son whom she thought had died in a car accident five years earlier.

Carrie was involved in the crash with the Irvines and a newborn Milo, and Peter was the only conscious adult after the accident. When he realized Josephine’s baby survived and his didn’t, he switched them, and he and Marissa raised Josephine’s baby as their Milo. The whole time, Marissa had no idea what her husband had done and was under the impression that the driver of the other vehicle had died by suicide.

What happens in All Her Fault the show?

In the show, Carrie shows up to the Irvine’s home with a gun to warn Marissa about the kind of man Peter is. Before she can get the full story out, Peter charges at her and uses the gun to kill her. However, he ultimately confesses his sins to his wife.

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Peter also confesses that he was the one who brought Milo back to safety after being called by Carrie’s father, Rob Murphy, with a ransom demand. He wound up killing Rob, then secretly rescuing Milo without his wife knowing.

Peter convinced Marissa not to go to the cops with the things he’d done and warned her that Milo would be taken away from them if she did. In the end, she took matters into her own hands by eating food that contained soy, which her husband is deathly allergic to, then kissing him on the lips.

There were plenty of other twists and turns along the way, too. Click here for a full breakdown.

All Her Fault, All Episodes, Streaming Now, Peacock