Set in 1988, the film takes place during the "Troubles" in Northern Ireland. While the Protestant Unionists wanted Northern Ireland (which is heavily occupied by the British army) to remain in the UK, most Catholics, on the other hand, wanted to have it integrated in the Republic of Ireland. As a Catholic, Martin McGartland (Jim Sturgess) joins the Irish Republican Army (IRA). However, since he's disgusted by the IRA's savage killings of political opponents and moles, Martin doesn't fully get involved in the IRA as much as his friend Sean (Kevin Zegers). This is why the British secret service sees the arranged arrest of Martin under a bright day.
In fact, Martin accepts to cross the line and works under the supervision of a British handler codenamed Fergus (Sir Ben Kingsley). Martin's job is to infiltrate the IRA (which is already done according to Fergus), inform Fergus about its activities and, in the process, save lives threatened by the IRA. Besides, since he fears for his family's and friends' security, Martin leads a double life. This means that even his girlfriend (Natalie Press) doesn't know a thing about what Martin does in life. Unfortunately, in 1991, Martin's cover gets blown because he leaked vital informations.
Obviously, Fifty Dead Men Walking is a strong film for it aims to be as authentic as possible despite admitting at the beginning that some events were altered. From the use of old news footages (to immerse us in the environment of the time), the gritty depiction of violence as it was practised by both sides (the British and the IRA), the casting of former members of the IRA and the use of Belfast as the shooting location, Kari Skogland shocks us and demonstrates, at the same time, her attention to details. However, some may find Fifty Dead Men Walking's script a little bit oversimplified because it doesn't expose Martin's inner conflict between his patriotism toward Ireland and his service in the British secret service.
As for the acting, Jim Sturgess is simply convincing when it comes to portray Martin's fears or feelings from daily life. As for Sir Ben Kingsley, although his performance might look bland on the surface, most of the things he says are rooted in the different layers of complexity in Fergus's thoughts since Kingsley's role is unfortunately underwritten. This is why the growing friendship between Martin and Fergus (hence, his desire to protect Martin) looks so convincing.
Finally, as Alan from Daily Film Dose puts it, "the Irish accents are laid on thick". Therefore, I only understood half of the dialogues. In other words, I felt like a Frenchman watching a French Canadian (be they from Quebec, New Brunswick or Manitoba) film without subtitles. Nevertheless, even if you're not a buff on Irish History, the film's plot is hopefully easy to follow.
Jim Sturgess, Ben Kingsley, Kevin Zegers, Natalie Press and Rose McGowan