The plot follows a private detective, an ex communist and former CIA agent, who travels from Barcelona to Madrid to discover the identity of the assassin of the leader of the Spanish Communist party who was stabbed during a blackout while presiding over a meeting of the party's central committee. The film is a thriller with ironic political overtones.
| Editing | Teresa Font | Editor |
| Production | Carmen Zorrilla | Casting |
| Directing | Vicente Aranda | Director |
| Writing | Vicente Aranda | Screenplay |
| Writing | Manuel Vázquez Montalbán | Novel |
| Production | Carlos Durán | Executive Producer |
| Production | José Antonio Pérez Giner | Executive Producer |
| Sound | Manel Camp | Original Music Composer |
| Camera | José Luis Alcaine | Director of Photography |
| Directing | Montserrat Buscató | Assistant Director |
| Directing | Yuyi Beringola | Script Supervisor |
