Except for a good taco, genealogist Lucy Lancaster loves nothing more than tracking down her clients' long-dead ancestors, and her job has never been so exciting as when she discovers a daguerreotype photograph and a journal proving Austin, Texas, billionaire Gus Halloran's great-great-grandfather was murdered back in 1849. What's more, Lucy is able to tell Gus who was responsible for his ancestor's death.

Partly, at least. Using clues from the journal, Lucy narrows the suspects down to two nineteenth-century Texans, one of whom is the ancestor of present-day U.S. senator Daniel Applewhite. But when Gus publicly outs the senator as the descendant of a murderer - with the accidental help of Lucy herself - and her former co-worker is murdered protecting the daguerreotype, Lucy will find that shaking the branches of some family trees proves them to be more twisted and dangerous than she ever thought possible.