Struggling with the loss of her child to Social Services, Ashley Colton (Abbie Cornish), a ragged beauty in her twenties, has survived a series of minimum wage jobs, trying to prove that she is fit to be a mother to regain custody of her son. When a visit from her father, a truck driver living in Mexico, brings Ashley to Nuevo Laredo, she discovers that he is smuggling immigrants across the border. Seeing a way out of the quicksand of her south Texas life, Ashley is lured into the role of a coyote. Her plan goes awry, and Ashley finds herself stranded with a young girl whose life is suddenly in her hands.