Allie and Thea's mother Arabella is getting married to her longtime sweetheart, Colonel Charlie "Brahman" Crandall of the Stockmen, the Independent Livestock Commission. Just as they're getting ready to share the good news, Colonel Crandall's daughter Sutheree disappears from her job as a state livestock inspector. When the sheriff finds her truck with a slashed tire, the call goes out Allie and her husband, Sam Foureyes, Private Eye. Sam and Allie load their gear in the truck and head out to the Black Hills from their Long Island mansion, while lawyer, pilot, and Allie's twin sister Theadelinda takes off from Montauk with Foureyes' junior partners, Brandon and Leo, to join the search for the missing agent.

When everyone arrives in South Dakota, they find an investigation that is as clear as mud. Not only that, but the same "unnamed agency" that almost ruined Sam and Allie's engagement has taken an interest in this case as well. So have the twins' incarcerated father and half-brother, and their friends from the Dos Huevos cartel. But why would the cartel abduct a cattle inspector? And why does that Wyoming ranch called the Lazy-Bar-T seem somehow familiar? It's up to Sam, his beautiful wife Allie, and her identical and flirtatious twin Thea to unravel all of the twists and turns to bring Sutheree home before the wedding can even happen. They may have to unleash the Tiger before anyone else goes missing, and the husband and wife detective team can cast their fly lines into the Black Hills legendary Spearfish Creek Canyon.