Na het verwerken van de dood van zijn broer Sergio, verheugt verpleger Mario zich op een nieuw hoofdstuk in zijn leven met de komst van zijn eerste kind. Maar wanneer kartelbaas Antonio Padin uit de gevangenis wordt ontslagen wordt Mario aangesteld om zorg voor hem te dragen. Al snel begint hij zich af te vragen of zijn zorgplicht belangrijker is dan de levens die deze man heeft vernietigd.
Ja! de film Quien a hierro mata is nu beschikbaar om te kijken op Netflix in Nederland.
| Art | Javier Alvariño | Art Direction |
| Costume & Make-Up | Silvia Neira | Makeup & Hair Assistant |
| Art | Paula Marín | Set Decoration |
| Art | Ventura Villar | Assistant Set Decoration |
| Production | Arantza Vélez | Casting |
| Costume & Make-Up | Erea Pérez | Makeup Artist |
| Costume & Make-Up | Susana Veira | Makeup & Hair |
| Directing | Lorena Vilas | Second Assistant Director |
| Directing | Paco Plaza | Director |
| Writing | Juan Galiñanes | Writer |
| Camera | Pablo Rosso | Director of Photography |
| Sound | Maika Makovski | Music |
| Writing | Jorge Guerricaechevarría | Writer |
| Costume & Make-Up | Vinyet Escobar | Costume Design |
| Production | Borja Pena | Producer |
| Production | Emma Lustres | Producer |
| Production | Mercedes Gamero | Producer |
| Production | Mikel Lejarza | Producer |
| Sound | Miguel Barbosa | Foley Artist |
| Sound | Gabriel Gutiérrez | Sound Designer |
| Costume & Make-Up | Paula Gámez | Special Effects Makeup Artist |
| Sound | Diego S. Staub | Foley Mixer |
| Costume & Make-Up | Nacho Díaz | Special Effects Makeup Artist |
| Sound | Irma Areta | Sound Post Supervisor |
| Costume & Make-Up | Pedro Raúl de Diego | Special Effects Makeup Artist |
| Sound | David Machado | Sound |
| Costume & Make-Up | Beatriz Antelo | Hair Designer |
| Sound | Maika Makovski | Original Music Composer |
| Directing | Juan Galiñanes | Second Unit Director |
| Directing | Ana Hernando | First Assistant Director |
| Sound | Kevin Hortigüela | Sound Effects Editor |
| Editing | David Gallart | Editor |
| Costume & Make-Up | Alberto Hortas | Special Effects Makeup Artist |
| Costume & Make-Up | Jordi Morera | Special Effects Makeup Artist |
| Sound | Alex Alcántara | Additional Sound Re-Recording Mixer |
| Sound | Yasmina Praderas | Sound Mixer |
| Sound | Kevi Aragunde | Foley Mixer |
| Sound | Ignacio Arrojo | ADR Recordist |
| Costume & Make-Up | Jesús García | Special Effects Makeup Artist |
| Costume & Make-Up | Raquel Álvarez | Special Effects Makeup Artist |
| Directing | Isa Escrigas | Third Assistant Director |
| Costume & Make-Up | Juan Olmo | Special Effects Makeup Artist |
| Crew | Óscar Franco | Stunt Coordinator |
| Visual Effects | Berta Coderch | Visual Effects Producer |
| Visual Effects | Félix Bergés | Visual Effects Supervisor |
| Visual Effects | Elena González | Visual Effects Coordinator |
| Crew | Fany Veiga | Stunt Coordinator |
| Visual Effects | Roberto García | Digital Compositor |
| Visual Effects | Clara López | Visual Effects Coordinator |
| Visual Effects | Cristian Martin | Digital Compositor |
| Crew | José Carlos Extremadura | Stunts |
| Visual Effects | Quico Noizeux | Digital Compositor |
| Visual Effects | José María Rincón | Visual Effects |
| Visual Effects | Antonio Miravalls | Visual Effects |
| Visual Effects | Laura Pedro | Visual Effects Supervisor |
| Crew | Gara Caballero | Visual Effects Editor |
| Art | Astrid Mayor Ramis | Title Designer |
