Elena is in charge of the library in a private school. His monotonous life is affected when a new child arrives at school with whom he is obsessed and whom he treats like his son. One day he decides to take him away, generating a crisis in his real mother, Andrea, who will do everything possible to get him back.

1951, Mexico City. After synthesizing the main component of the contraceptive pill, young scientist Luis Miramontes deals with the religious and personal consequences of his groundbreaking invention.