Denis (Jonny Lee Miller), a man whose life is shattered by a single criminal act in which his young wife is killed in a bungled break-in attempt by a career criminal called Ricky Barnes (Andy Serkis). Denis, for whom life up to then had seemed perfect, cannot cope with his loss, and dedicates his life to tracking down the man responsible. It is a pursuit which requires him not only to be sent to jail, but to be sent to the worst - or, as the prison service would have it, the most secure - jail in Britain: Sullen Voe.