Reese Witherspoon is an rigidly by-the-book, penal code-reciting San Antonio, Texas police officer named Cooper, whose past mistakes in the line of duty has relegated her to the shame of desk and evidence room duties these days. However, due to a law that a female cop must be involved in the transport of a female witness (Sofia Vergara) named Daniella Riva, she's back out in the field in order to protect the wife of an informant to testifying against Vicente Cortez, the murderous leader of a major drug cartel, as they travel from San Antonio to Dallas for his trial. However, between Cortez's men and some cops on the take, the odd couple that can't get along must find away to stay alive, while also not trying to kill each other in the process.