Married couple Elena and Ernesto desperately seek a bone marrow donor for their adopted son Nicolás, who suffers from leukemia. A humble mechanic named Pedro is stunned to discover the boy is his biological son, changing everyone's lives.

Nicolás (Leonardo Herrera) is a six-year-old boy suffering from leukemia and to recover he needs a bone marrow transplant. In such a situation, the adoptive parents of the child, Elena (Eva Cedeño) and Ernesto (Jorge Salinas) will take on the task of searching for the biological father. Thus, they arrive at the mechanical workshop where Pedro (José Ron) works to expose the situation, at which point the young man learns that he had a son from a relationship years ago.