We Were Liars' sequel novel, Family of Liars, confirmed what the Sinclair siblings (aka the moms of Cadence, Johnny, and Mirren) did in their own Summer 16 that still haunted them in the present day. Amazon Prime Video's mystery drama series pushed the wealthy Sinclair family to the forefront as their lavish lifestyle and dark secrets are slowly unraveled. While the series primarily focused on Cadence Sinclair Eastman's (Emily Alyn Lind) story, We Were Liars also highlighted her mom and aunts, Penny, Carrie, and Bess, alongside their shared trauma and a preview of a sinister event that took place when they were 16 years old.
Based on E. Lockhart's novel and developed for streaming by Julie Plec and Carina Adly Mackenzie, We Were Liars is an eight-episode series that follows Cadence's journey in trying to piece together her memories in Beechwood after suffering a traumatic brain injury.
The series, which premiered on Prime Video on June 18, 2025, has an incredible cast led by Emily Alyn Lind, David Morse, Candice King, Mamie Gummer, Rahul Kohli, and Wendy Crewson.
What Did the Moms Do When They Were 16? We Were Liars Accident & Punishment Explained
As part of the complex Sinclair family tree in We Were Liars, Carrie, Penny, and Bess have a dysfunctional relationship. They resent one another as they vie for their father's (Harris Sinclair) validation and inheritance while also trying to gain possession of their mother's (Tipper Sinclair) necklace (which symbolizes elegance and perfection for whoever wears it).
A bigger reason the Sinclair daughters hate each other is that Harris consistently makes them compete for his love and affection (despite the fact that his true favorite daughter is the late Rosemary Sinclair, who died when she was young).
However, We Were Liars hinted that an inciting incident in the past truly defined the trio's sisterly bond all these years. In Episode 8, Carrie and Bess reflect on the deaths of their children, Mirren and Johnny.
As the eldest, Carrie told Bess that she thinks that "losing them was [their] punishment" for what they did when they were 16 in their version of Summer 16:
Carrie: "Sometimes I think losing them was our punishment. Like that one tiny ember was sent from God, or the universe, or Beechwood Island."
Bess: "Punishment for what?"
Carrie: "For what we did in Summer 16. The summer... the summer I was 16. Because then I think if it was our punishment, Penny wouldn’t have been spared, right?"
Bess: "Yeah."
While the series did not explicitly reveal what the sisters did when they were 16, We Were Liars' prequel novel, Family of Liars, confirmed what truly happened and is quite tragic. At the center of the book's story is Carrie and her tumultuous relationship with a guy named Pfeff.
Carrie and Pfeff's immense love for each other appeared genuine, and both were poised for a happy ending. The pair's bond was eventually shattered when Pfeff cheated on Carrie with her sister, Penny, and the sisters' already strained relationship took a turn for the worse.
As told from Carrie's perspective in the book, Bess told Carrie that she killed Pfeff out of self-defense for assaulting their sister, Penny. Pfeff died after he was bashed in the head with a loose board from the pier.
However, not everything seems to be the case since Carrie lied about the truth. Instead of Bess killing Pfeff, it was actually Carrie who bashed him in the head after being jealous of Pfeff and Penny's intimate relationship.
Despite their strained relationship, the three sisters worked together to get rid of Pfeff's body and create a fake scenario where they would make it seem that he drowned and was eaten by sharks.
Only the three Sinclair sisters knew the truth about what happened that night, and Carrie believed that losing their children (Johnny and Mirren) in the present day served as punishment for what they did.
How The Sinclair Sisters' Secret Sets Up We Were Liars Season 2
We Were Liars ended with the reveal that Carrie is conversing with his dead son, Johnny. Similar to Cadence, she can also see ghosts, and her final conversation with Johnny sets up an intriguing and more complex Season 2 for the Prime Video series (read more about what happened to Johnny in We Were Liars).
During their conversation, Carrie told Johnny that he thought he had already left and moved on to the afterlife. However, Johnny said that he doesn't think he can, implying that he needs to know more about his mother's past before finally moving forward:
Carrie: "I thought you'd left."
Johnny: "I don't think I can."
The book, Family of Liars, was told from Carrie's perspective while telling Johnny everything. As a result, this would mean that a potential Season 2 of We Were Liars would bring the story of the young Sinclair sisters to life, Rosemary's death, and the tragic incident involving Pfeff.
Doing this would provide more context as to how complicated the Sinclair family is from the inside (which is far different from the perfect image they are trying to portray to the public).
