The Harkey name was famous for pecan harvesting in Texas. So when the matriarch with a powerful grip on the family fortune went missing, investigators focused on the family tree. Turns out, the plot was more tangled than the branches of a pecan tree.

A seemingly healthy doctor collapses at home and is rushed to the emergency room, where a blood test reveals she has been the victim of cyanide poisoning, turning a medical mystery into a murder mystery.