"We Were Liars," by E. Lockhart, has garnered significant attention, particularly for its tragic and twisty narrative structure. The story revolves around the wealthy Sinclair family, who spend their summers on a private island called Beechwood. Cadence Sinclair Eastman, the protagonist, and her cousins – Johnny and Mirren – along with Gat Patil, form a close-knit group known as "the Liars." The novel unfolds as a coming-of-age mystery, gradually revealing dark secrets beneath the surface of the seemingly perfect Sinclair family.

Each summer on Beechwood Island holds a special significance for the Sinclairs, but Summer Fifteen changes everything. During this summer, Cadence suffers a severe head injury, resulting in memory loss. She struggles to recall the events leading up to her accident, and the other Liars remain tight-lipped, leaving Cadence to piece together the fragments of her past. This sets the stage for a narrative filled with unreliable narration and hidden truths.

The central mystery revolves around what happened on the night of Cadence's accident. As she returns to the island in subsequent summers, the sense of unease and the fragmented nature of her memories intensify. The reader is drawn into Cadence's quest for answers, experiencing her confusion and frustration as she tries to unravel the truth.

The shocking twist is revealed towards the end: Mirren, Gat, and Johnny are all dead, having perished in a fire. Throughout the summer that Cadence is seventeen, she has been interacting with their ghosts, who are waiting for Cadence to remember the events of Summer Fifteen. The fire was intentionally set by the Liars as a means to rebel against the toxic legacy of the Sinclair family and their obsession with money and inheritance. In a drunken state, they sought to make a statement by burning down the family's main house, Clairmont. However, their plan went horribly wrong.

Cadence was the only survivor of the fire, which was caused by the explosion of a gas line. She had run out of the house after setting the fire and attempting to save her grandmother’s black pearls. Gat, Johnny, and Mirren were all trapped inside the burning house. The revelation that she has been interacting with ghosts and the realization of her role in their deaths lead to a climax of grief and guilt.

The final episode reveals the circumstances surrounding each of the Liars' tragic ends. Mirren, conflicted about destroying a painting her mother had tried to save, hesitated, costing her precious time. Johnny was similarly delayed. Gat, fearing the worst when no one emerged from the house, ran inside to save them, ultimately meeting his end as well. Cadence, outside the house, was thrown into the water by the explosion.

The ending explores themes of guilt, responsibility, and the consequences of one's actions. Cadence must grapple with her role in the tragedy and find a way to move forward. The ghosts of the Liars eventually depart, leaving Cadence with the burden of her memories and the resolve to live a life that honors their memory. In the end, Cadence decides to break free from the Sinclair family's lies and expectations. She refuses to perpetuate their façade of perfection. The final scene shows Cadence stealing the family boat and leaving Beechwood, symbolizing her departure from her old life.