Virginian Robert S. Carlisle came to the American West to seek his fortune and married into a land-grant family. Following the death of the family patriarch, Don Isaac Williams, Carlisle cheats his wife of her share of 22,000 acres and attempts to do the same to his sister-in-law. When Los Angeles Sheriff Andrew Jackson King meets Carlisle by chance, he is immediately suspicious of Carlisle's questions about the death of his father, Sheriff Samuel King years earlier. He also learns of Carlisle's plan to swindle land from the Isaac Williams family. As law officers, King and his brothers initiate legal action against Carlisle to stop his theft, leading to the bloodiest duel ever fought in Los Angeles. But could Carlisle's grudge have any connection to the murder of his father, Samuel King? A.J.'s L.A., based on a true story, describes the very early days of Los Angeles as experienced by the family of author, Victor Haddox.