María Álvarez, a 17-year-old Colombian girl (played by Catalina Sandino Moreno), works in sweat shop-like conditions at a flower plantation to help support her family. However, after finding herself pregnant by her boyfriend, whom she does not love, and being unjustly treated by her boss, she quits and decides to find another job, despite her family’s disapproval. On her way to Bogotá to find a new job, she gets offered a position as a mule — one who smuggles drugs by swallowing drug-filled pellets. Desperate, she accepts the risky offer and swallows 62 wrapped pellets of cocaine and flies to New York City. After a close call at the US Customs (she was about to be X-rayed, until customs found out she was pregnant), she is set free and sent to a hotel where she is to remove the pellets from her body. The traffickers arrive to take the drugs. To retrieve the pellets from Lucy, a fellow mule who had died when one of the pellets ruptured inside her, the traffickers had cut open her stomach, then disposed of her body. After seeing this ruthless world firsthand, Maria decides to escape the drug-trafficking cartel.
Her story becomes one of determination and survival like that of many other immigrants in the United States, although she knows nothing about the country and had originally planned to go back to Colombia.The economic hardships of Colombia and the working environment for illegals in the US are both accurately represented. Eventually realizing that her choices affect other people, she emerges with the grace that will carry her forward into a new life. In the end Maria lives her life in the United States.