Javier Navarro, a Falangist, is ordered to infiltrate Republican Madrid to deliver a message to a member of the Fifth Column.
| Actor | Role |
|---|---|
 Rafael RivellesJavier Navarro (Spanish cut) | Javier Navarro (Spanish cut) |
 Fosco GiachettiJavier Navarro (Italian cut) | Javier Navarro (Italian cut) |
 Conchita MontesCarmen | Carmen |
 Juan de LandaAmalio | Amalio |
 Manolo MoránCaptain Salmerón | Captain Salmerón |
 Blanca de SilosMercedes | Mercedes |
| LLuis López EstradaAnarchist Militiaman | Anarchist Militiaman |
| AArgimiro GuerraCarmen's Brother | Carmen's Brother |
| MManuel MirandaCheca Chief | Checa Chief |
| ÁÁngel MarreroClandestine Radio Announcer | Clandestine Radio Announcer |
 Carlos Muñoz ArosaCommunist Militiaman | Communist Militiaman |
| CCrisanta BlancoDoorwoman | Doorwoman |
 José MartínFamish Militiaman | Famish Militiaman |
| CCalisto BertramoSoviet | Soviet |