Tracy López is a young nurse who lives in Los Angeles with her boyfriend, Sam Ross. Their relationship is relatively quiet, until Tracy accidentally witnesses a murder committed by her boyfriend. Frightened, she goes to the Police Department telling what she saw. She subsequently finds out that Sam has been lying to her the whole time as he actually has criminal connections to the mafia. 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. Following the instructions they give her, she flees the country to Mexico City. 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. But as a doctor, on the other hand, he is noble and compassionate.
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.
