Al filo de la muerte (English: At the edge of death) is a Mexican telenovela produced by Emilio Larrosa for Televisa in 1991.
Tracy López is a young nurse who lives in Los Angeles with her boyfriend, Sam Ross.
The police introduce Tracy to the Witness Protection Program, where she is given a new identity: from now on her name will be Mariela Foret.
There she is employed in a prestigious hospital belonging to the respected cardiologist Francisco Riquer, who as a person is hard and full of remorse, because he could not save his wife and son, who died in the 1985 Mexico earthquake.
Francisco and Tracy will meet and despite the initial disagreements they have, they will end up falling in love; but Sam, furious at having been betrayed by his girlfriend, will travel to Mexico not willing to let her be happy with the doctor.