The lowcountry of South Carolina, at a barbecue thrown by Diane English Stiftel, her brother Floyd, and her parents to celebrate her son's engagement, is where By Invitation Only begins. On this gorgeous, magical night, the bride's father, Alejandro Cambria, a wealthy power broker whose unbelievably successful career in private equity made him one of Chicago's celebrated elite, discovers the limits and possibilities of cell phone range. Meanwhile, the mother of the bride, Susan Kennedy Cambria, a volunteer fund-raiser who believes herself deserving of every square inch of her multimillion-dollar penthouse and imaginary Carrara marble, learns about moonshine and dangerous liaisons. Soon By Invitation Only zooms to Chicago, where the unraveling accelerates. Nearly a thousand miles away from her comfortable, familiar world, Diane is the antithesis of the bright lights and super-sophisticated guests attending her son Fred's second engagement party. Why a second party? Maybe it had been assumed that the first one wouldn't be up to snuff? Fred is marrying Shelby Cambria, also an only child. The Cambria's dearest wish is for their daughter to be happy. If Shelby wants to marry Frederick, aka Fred, they will not stand in her way -- although Susan does hope her friends won't think her daughter is marrying more than a few degrees beneath her socially. At the same time, Diane worries that her son will be lost to her forever. By Invitation Only is a tale of two families, one struggling to do well, one well to do. and one young couple -- the privileged daughter of Chicago's creme de la creme and the son of hardworking southern peach farmers.