We Were Liars is about Cadence Sinclair who is part of the rich, white Sinclair family. Every summer her family goes to her grandfather's island and lives there for the whole summer. She is the oldest of 6 other cousins; Johnny, Mirren, Will, Liberty and Bonnie (called "the twins"), and Taft. Johnny's friend, Gat, also comes to the island every year. Cadence falls in love with Gat and they have a very complicated on again, off again kind of relationship.
One summer Cadence has an accident. She is told that she was found on the beach with no clothes and suffered a head injury, but she does not remember the actual event. For the rest of the school year she struggles with migraines and misses a lot of school. The next summer, Cadence's mother does not think it is a good idea for her to go back to the island yet, so she sends Cadence on a trip with her dad to Europe. Cadence is gone the whole summer and emails her cousins on the island, but they don't email her back.
Two summers after her accident her mother allows her to go back to the island, but things aren't the same. Her grandfather has built a new house called the "new Clairmont," and has gotten rid of everything from the old house. It is new and fresh and everything from the old house is gone. All of her grandmother's things and all of the pictures are all gone. Cadence still struggles with headaches, but her mom makes her be "normal." Cadence is still expected to go to dinner at the new Clairmont, even though Johnny, Mirren, and Gat don't.
As the summer goes on Cadence starts to remember more things from her accident. She remembers that the reason why the family built a new Clairmont is because her and Johnny and Mirren and Gat burnt down the last one. She remembers how they were tired of their family being greedy about who her grandfather would leave everything to that they decided to destroy it. She remembers the plan they had set and how it went all wrong. She remembers how the dogs were trapped inside and how they burnt to death. And she remembers how Johnny, Mirren, and Gat were also trapped in the house.
She couldn't remember the accident because her brain wouldn't let her because of the guilt she felt from it. And she discovered that Johnny, Mirren, and Gat weren't real. They were ghosts, or her imagination, but they had been dead for the past two years, and her brain wouldn't let her remember because it was too painful.
