Two months after prominent lawyer Sanford Whitaker's violent death in the spike-fenced park next to his Kenilworth home, his family gathers to sort out his estate. The police determined that he shot himself accidently - but are they right? It has been twenty years since he left his wife and children to marry former actress Cece Cavalier. His older children - Ellen, an ambitious lawyer living in the Winnetka ravines with her husband Mason, a financial planner -- and Alan, an Evanston lawyer married to Jessica, a preschool teacher -- despise Cece, and resent Clara, Sanford's beloved teenage daughter. Surprisingly, Sanford has died without a will, leaving everyone to struggle with the fallout of his sudden death. North Shore prosecutor Meredith Bennett has her own problems. Meredith's ex-husband, Dr. Alexander Bennett, left Meredith and their children five years ago to marry Shawna, his young receptionist. Regretful, he now hopes to return to Meredith, just as Shawna gives birth to their first child. The Poisonous Tree examines the awesome forces of love and darkness that can expand families -- or destroy them.