Playing out like a feature length episode of OZ meets Banged Up Abroad, Cell 211 is a gripping prison drama.

Juan (Ammann) starts a new job as a prison guard tomorrow but he turns up today to get a feel for the place. Big mistake. As Juan is shown around his new workplace, something falls from the ceiling, hitting him in the head. Dazed, he is taken to Cell 211 to recover but before he can be moved to the infirmary a riot breaks out. Panicking, Juan passes himself off as a new prisoner to the charismatic ringleader Malamadre (Tosar), who has organised the riot to protest the shoddy conditions in which the prisoners are held. However, when the media get news that there are three ETA prisoners inside, the whole situation turns political and it's only a matter of time before Juan's identity is revealed.

Monzon isn't a director who likes to hang about: Juan isn't in the prison ten minutes when all hell breaks lose and, bar the odd flashback to a quiet morning Juan spends with his pregnant wife Elena (Etura), the director likes to pile tension upon tension. The distrust Malamadre's lieutenants have for Juan threaten his cover every minute: when the news of the riot leaks to the press, the families of prisoners throng at the gates to find out who has been killed and create a frenzy; and the SWAT team that have assembled on the roof need no excuse to break in. Everything closes in around this small prison block and Monzon delights in tightening the screw.

The director, who adapted the script from Francesco Perez Gandul's novel with his long-time collaborator Jorge Guerricaechevarria, draws parallels between the prisoners and those in authority. Juan's journey from a fresh-faced softy into a hardened criminal is believable and illustrates that the chasm between good and evil isn't that wide. The guards and politicians are seen as vicious, cruel and duplicitous. Malamadre may be a lethal killer but he is at least a man of his word.

Cell 211 can get a little convenient, however, and Monzon fails to really hammer home the ruthlessness of the prisoners but this drama is one that ticks over nicely.