Peacock's 'All Her Fault' Adaptation Deviates from Novel, Adds Thrilling Twists

Peacock's new mystery series 'All Her Fault', which premiered in November 2025, is based on a novel by Andrea Mara. However, the TV adaptation has made several significant changes to the original story.

The show follows a mother named Marissa (Sarah Snook) whose son, Milo, disappears during his first playdate. As the search for Marissa's child uncovers secrets about those closest to her, the series has introduced new twists and turns that were not present in the book.

One of the most notable differences is the way the show has developed the characters of Brian and Lia. In the novel, Brian seemed unrecognizable from the version written by Megan, the show's creator. Similarly, Lia was largely out of the picture in the book, as she was living in New York while the Irvine family was in Dublin (which was changed to Chicago for the TV series).

The show has expanded on these characters, revealing that Brian was disabled following an accident when he was younger, and that Lia had a past substance abuse issue. Lia was also involved in a secret relationship with Marissa's business partner, Colin, before his death.

These changes have added new layers of complexity to the story, creating a more thrilling and unpredictable viewing experience for audiences. The show has also made adjustments to the circumstances surrounding the deaths of various characters, further deviating from the original novel.

Overall, Peacock's 'All Her Fault' has taken the core mystery of the book and added its own unique twists and turns, making for a captivating and suspenseful television adaptation.