In Dos Rios, Texas, life is all about borders, and what happens when you cross the line. Nothing is simple in a border town like Dos Rios, in the Rio Grande Valley of Texas. Even for high school students Fabiola Garza and her younger sister Alexis, whose parents run a local Tex-Mex restaurant, Dos Rios is full of borders — where you should go, who your friends should be, which boy you should date. Dos Rios is also full of opportunities, but it's a town divided, between the haves and the have-nots, the Whites and the Mexicans-Americans, the Texans and the Mexicans, the legal and illegal. But through it all, the Garza sisters have each other. Water can be crossed, but blood is the ultimate borderline, no matter what.