A child is witness to an assault on a monk by the gang of Lorenzo the Fifth. The monk escapes and takes refuge in the estate of Doña Carlota, a countess who lives with her son Juan and daughter Beatriz. Basilisa, the maid, conjures the devil to free her son from an irreversible illness, but to do so the evil must be transmitted to an innocent soul, and for that she chooses Beatriz. The child begins to be the victim of a possession, for which everyone blames the monk.
| Directing | Gonzalo Suárez | Director |
| Writing | Ramón del Valle-Inclán | Story |
| Writing | Santiago Moncada | Screenplay |
| Writing | Gonzalo Suárez | Screenplay |
| Production | Julián Esteban Gómez | Producer |
| Production | Luis Méndez | Producer |
| Production | José S. Vaquero | Line Producer |
| Sound | Fermín Gurbindó | Original Music Composer |
| Camera | Carlos Suárez | Director of Photography |
| Editing | Antonio Gimeno | Editor |
| Art | Ramiro Gómez | Set Decoration |
| Costume & Make-Up | Antonio Muñoz | Costume Designer |
| Costume & Make-Up | Toñy Nieto | Makeup Artist |
| Costume & Make-Up | Carlos Nin | Key Makeup Artist |
| Costume & Make-Up | Marina Pavía | Assistant Makeup Artist |
| Costume & Make-Up | Josefa Pérez | Hairstylist |
| Directing | Rodolfo Medina | Assistant Director |
| Art | José Luis del Barco | Assistant Set Decoration |
| Art | José Luis Merino | Property Master |
| Sound | Jesús Jiménez | Sound Mix Technician |
| Crew | Pablo Pérez | Special Effects |
| Camera | César Cruz | Still Photographer |
| Camera | Fernando Fernández | Assistant Camera |
| Camera | Julio Madurga | Camera Operator |
| Lighting | Fernando López | Gaffer |
| Camera | Alberto Vega | Second Assistant Camera |
| Costume & Make-Up | Juana Ramírez | Costumer |
| Editing | Mercedes Gimeno | Assistant Editor |
| Editing | Ricardo Gimeno | Assistant Editor |
| Directing | Marisa Ibarra | Script Supervisor |
| Art | Alberto Corazón | Title Designer |
| Production | José Garijo | Production Assistant |
