The witty, dramatic, and fiercely tender story of a Southern family whose prodigious charms are matched only by their propensity for tragedy   "Miss Cade passing." The letter arrives with little fanfare and fewer details, yet the meaning is clear: The Cade family of Covington, Louisiana, has cause to grieve once more.   Called home from her first book tour, author Rory Cade boards a flight from New York to New Orleans. In the next seat, her brother-in-law and former lover Johnny Killelea, now a famous journalist, drinks Scotch and stirs up memories of events long past but never forgotten. As the plane flies south through stormy skies, Rory recalls her family's turbulent history: her mother and stepmother's early deaths; her brilliant and charismatic father's descent into alcoholism; and the romances, heartbreaks, and secrets that shaped her own life and those of her two sisters.   As the tumultuous events of the 1960s unfold, the Cades are pulled apart by their private demons of money, madness, and lust. Exquisitely crafted by one of the South's finest storytellers, Slow Poison is the rich and evocative tale of this star-crossed family's triumphs and misfortunes.