"We Were Liars" is a 2014 young-adult novel by E. Lockhart that centers on the wealthy Sinclair family who spend their summers on a private island. The story revolves around Cadence Sinclair, who suffers from memory loss following an accident and struggles to recall the events of a fateful summer. The novel explores themes such as the consequences of mistakes, family conflicts, privilege, and the facade of a perfect family. The plot reveals that Cadence and her three cousins, known as the "Liars," conspired to burn down the family's mansion to stop family disputes. Tragically, during the fire, Cadence's actions unintentionally lead to the deaths of the other three Liars. The novel closes with Cadence grappling with the truth and the emotional aftermath of the event. Additionally, "We Were Liars" has been adapted into an American psychological thriller TV series, which premiered on Amazon Prime Video in June 2025, depicting similar storylines and characters from the book.