In Fifty Dead Men Walking, which is based on a true story, Martin McGartland gets picked up by the British police to spy on the IRA. He works his way through the system, climbing the ladder as he gets more power within the IRA. But he eventually gets found out and has to find a way to escape with his life. Fifty Dead Men Walking stars Ben Kingsley and Jim Sturgess and looks like it will be an action-packed thriller with an authentic British feel to it. Watch the trailer after the jump.