One of the staff girls at The Golden Mousetrap, a city nightclub, has been stabbed and is barely alive; a doctor is examining her in a dressing room. Inspector Simón leads the investigation supported by the night shift inspector Arévalo. The club management asks that nobody leave the place, since everyone there must cooperate with the police and being interrogated.
| Writing | Luis de los Arcos | Story |
| Directing | José María Forqué | Director |
| Writing | Luis de los Arcos | Screenplay |
| Sound | Félix Álvaro | Sound Editor |
| Sound | Alfonso Carvajal | Sound Editor |
| Sound | Ramón Vives | Original Music Composer |
| Camera | Heinrich Gärtner | Director of Photography |
| Editing | Julio Peña | Editor |
| Writing | Alfonso Paso | Screenplay |
| Writing | José María Forqué | Screenplay |
