Rosario (Kate del Castillo) is hardworking and conscientious, but she's also an illegal immigrant, which means she has no recourse when her employer (Jacqueline Voltaire) decides to let her go. It's just one more roadblock for Rosario, who's been in Los Angeles for four years, hoping to bring over her 9-year-old son Carlitos (Adrian Alonso). UNDER THE SAME MOON follows both her efforts to gain legal status (she's tempted by the marriage offer of a very nice green-card holder) and Carlitos' attempts to reach her. After his grandmother's unexpected death leaves him alone in his small Mexican town, he undertakes a border crossing, hiding in the car of a couple of American students, including Marta (
America Ferrera). He then finds himself alone and on the road, bothered by a junkie, a child-sex trafficker, border patrolmen, INS agents, and assorted other adults. At last he falls in with a hitchhiker, Enrique (Eugenio Derbez), who helps him find his long-lost father in Tucson, and afterward, get to L.A., where there are still more challenges to overcome.