The novel is a coming-of-age story about a young boy named John Egan who lives in Ireland with his parents. John possesses an unusual gift for detecting lies, which he believes makes him a "human lie detector." As he navigates the complexities of adolescence, his family's financial struggles, and his own emotional turmoil, John's unique ability begins to cause more harm than good. The story explores themes of truth, deception, and the lengths one will go to preserve self-identity.

The novel follows the turbulent journey of an Australian man who travels to Ireland with his young daughter to reunite with his wife, only to discover upon arrival that she has mysteriously disappeared. As he searches across Europe for his missing wife, grappling with the uncertainty of her fate and the challenge of caring for his daughter alone, he is forced to confront his own shortcomings and the reality of his crumbling marriage. The narrative is a haunting exploration of hope, despair, and the complexities of love and identity, set against a backdrop of richly depicted landscapes that mirror the protagonist's inner turmoil.