P.I. Sierra Martindale could have been the best in the business. But life threw her one hell of a curve. Her fearless pursuit of the truth made P.I. Sierra Martindale unstoppable - right up to the day she collapsed in the midst of a dangerous case. After a lifesaving transplant, Sierra found herself with another woman's heart beating in her chest - and an eerie presence telling Sierra her donor's death was no accident. She owed it to this stranger to solve the dark mystery of what had happened to her. Even if it led Sierra into greater danger than she had ever known - and into the arms of the haunted stranger who had loved her donor, and lost her.