Adapted from "Le mortel baiser", a stage play by French writer Loïc Le Gouriadec (also known as Paul Gury). The story follows Cecilia, the daughter of a wealthy and conservative family, who is about to marry the son of the town's mayor. When a physician specializing in venereal diseases arrives in town, he examines Cecilia's fiancé and informs him that he is still suffering from syphilis, which has advanced significantly since he contracted it years earlier.
| Actor | Role |
|---|---|
 Miguel Ángel Ferriz Sr.Dr. Juan Estrada | Dr. Juan Estrada |
 Matilde PalouMatilde | Matilde |
 Magda HallerCecilia | Cecilia |
 Julián SolerRaymundo Vázquez | Raymundo Vázquez |
| CConchita SáenzDoña Amelia | Doña Amelia |
 Manuel NoriegaDon Maximino | Don Maximino |
| MMargarita CortésRosita | Rosita |
| MMiguel WimerDon Adalberto Vázquez | Don Adalberto Vázquez |
 Joaquín CossSeñor cura | Señor cura |
 José Ortiz de ZáratePapá de Rosita | Papá de Rosita |
| CConsuelo SegarraDama honorable | Dama honorable |
| MMaría del Carmen MartínezDama honorable | Dama honorable |
 Carolina BarretMujer fumando (uncredited) | Mujer fumando (uncredited) |
 Victorio BlancoSacerdote (uncredited) | Sacerdote (uncredited) |
| LLeonor GómezMujer cantina (uncredited) | Mujer cantina (uncredited) |
 Víctor JuncoInvitado (uncredited) | Invitado (uncredited) |
| AAurora RuizMujer ventana (uncredited) | Mujer ventana (uncredited) |
| VVictoria SastreMujer ventana (uncredited) | Mujer ventana (uncredited) |
 Hernán VeraInvitado a fiesta (uncredited) | Invitado a fiesta (uncredited) |