Isa Wilde, mother and civil service lawyer, is the first-person narrator and the protagonist of The Lying Game. Isa lives with her partner of 10 years, Owen, and their six-month-old baby daughter, Freya. Isa keeps her past hidden from Owen. Lying is a fundamental part of Isa’s life: She believes lying is necessary to protect herself and her friends.

Isa learns her lying ways at boarding school. At the age of 15, Isa’s home life is bleak: her mother is dying from cancer, and her grief-stricken father sends both Isa and her brother away to separate boarding schools. At Salten House, no one knows Isa, and she picks a new identity. Isa chooses to be a bad girl: becoming exclusive friends with Kate, Thea, and Fatima. Isa finds lying “fun” as she plays the Lying Game with her friends, targeting and making fun of other girls at the school. Her friendship and the poisonous game ostracize Isa from other students and people in town, but at the time, Isa does not care. At Salten House, Isa learns the power of friendship, explores typical teenage behaviors, and ultimately comes of age.