Hoy no se fía, mañana sí: Madrid, 1953. Gilda is a young orphan who difficultly survives in a ruined, post-civil war Spain. Opportunistic, ambitious and ruthless, she dreams of becoming a radio speaker and wants to get an official union card, a requisite for the job. She doesn't hesitate in joining an ultra-catholic fraternity and to become a police informant. But the suicide in prison of her aunt, a militant Republican, threatens to ruin her plans. She has only one solution left : to use her charms.