Seventeen-year-old Ella Gatz is alone when the thief enters her father's mansion on Halloween night. Ella fights the intruder but fails to stop the theft of Her Heart, her mother's favorite painting. Ella mourns the loss of the only remaining piece of the mother she lost, and when her father, CEO of a security firm, refuses to report the crime for fear of the humiliation he will face at having his security system fail in his own home, Ella determines to hunt down the culprit and reclaim Her Heart.

The only hint to who the thief may be is a long, pink-and-blond hair. Finding her thief will become Ella's first move in a dangerous game of wits that exposes family secrets and could lead to her family's financial ruin.