Al filo de la muerte is a Mexican telenovela produced by Emilio Larrosa for Televisa and originally broadcast on Canal de las Estrellas from June 17, 1991, to February 21, 1992. Created by Fernanda Villeli and Marcia Yance, the telenovela stars Humberto Zurita and Gabriela Rivero. The story follows Tracy López, a young nurse living in Los Angeles whose life is turned upside down after she witnesses her boyfriend commit a murder. Placed in the Witness Protection Program under the new identity of Mariela Foret, she flees to Mexico City, where she begins working at a prestigious hospital. There she meets cardiologist Francisco Riquer, and despite their difficult first encounters, they fall in love while facing danger, revenge, and the lingering threat of Tracy's criminal past.