Cora Beth Williams and Nat Hinson are narcotics agents. Cora Beth, an agent for the DEA, is betrayed by her supervisor. Hired killers are waiting when she arrived in Rio Valley. Nat, a narc with the Texas Department of Public Safety, rescues her and they became partners with the Texas DPS narcotic division. Cora Beth and Nat are joined by Kim Turner, Will Coggins, Maria Nino, and Vivian Hays to uncover the cartel smuggling drugs into Texas. The team is sent to Harlingen when they learn a high-level meeting is scheduled for the cartel. The three couples work together and the ring is arrested or killed. Maria and Hays are sent to El Paso when they learn another branch of the ring is working out of the El Paso DEA office. Horace Grant, the rogue DEA supervisor, disappears and Nat and Cora Beth learn Mable Grant, the wife of Horace, has been abducted. Their assignment is to find Mabel and locate Horace Grant. Relationships develop between the three couples in spite of their dangerous assignment along the Texas border where the drug war rages in Mexico. Could their romance be lasting, as they are in a violent occupation where life is cheap and drug merchants shoot first and never ask questions later?