The "lies" in the title refer to the hidden truth of Ella's adoption and her biological roots.

The story follows , a 17-year-old girl living a seemingly normal life in Kent, England. However, Ella harbors a dark secret: a destructive alter-ego she calls "Bella" (short for "Bad Ella"). Bella is a voice in her head that urges her toward violent or reckless impulses, which Ella struggles to suppress to protect the people she loves.

Reviewers have praised the book for its and emotional intensity , particularly in how it captures the "rage at adults' deception". Some critics noted that while the plot is engrossing, certain elements—like the rapid "love at first sight" romance—can feel a bit unrealistic. Reviews - La verdad y las mentiras de Ella Black