All her life Ellie Enderlin had been known as Lila's sister. Until the day Lila, a top math student at Stanford, was murdered, and the shape of their family changed forever. In the aftermath of her sister's death, Ellie entrusted her most intimate feelings to a man who turned the story into a bestselling true crime book--a book that devastated her family and identified one of Lila's colleagues as the killer. Twenty years later, Ellie is now a professional coffee buyer, an inveterate traveler who is incapable of trust. In a chance meeting with the man accused of the crime, she comes into possession of the notebook filled with mathematical equations that Lila carried everywhere. Stunned, she will return home to San Francisco to explore the mysteries of Lila's notebook and begin a search that will lead her to a centuries-old mathematical puzzle, to the motives and fate of the man who profited from their family's anguish--and to the deepest secrets even sisters keep from each other.

930,Lexile.

Reading Counts RC,High School,6.6,22,Quiz: 44501.

Accelerated Reader AR,UG,6.4,15.0,127335.