River Brookes is a young medical school student from New Zealand studying in the US. During a break in her last year of medical school she decides to explore the southwest US. She finds herself lost in the deserts of southwest Texas and falls afoul of Mexican drug cartels. She is rescued by a wealthy local rancher and his family and finds herself embroiled in a clandestine border war. The Martingale family, longtime ranchers and landowners and their friends and employees become the unofficial enforcement force for a top secret state department operation, working to stymie the drug cartels and their operations along the US border with Mexico. Keith Martingale, the Patriarch of the Martingale family, is determined to keep his ranch and his family on the land that they have owned for more than 100 years. This determination leads him into the world of international intrigue and business. In the midst of the violence and intrigue, River finds what she has never had, a family, love and acceptance.