Luther is a detective struggling with his own terrible demons, who might well be just as dangerous as the depraved murderers he hunts. On a moral crusade, too often with only his convictions for company, John Luther is a brilliant but deeply troubled man, a philosophical cop possessed by the insoluble problem of evil and justice in a Godless world. Luther shines a light where others fear to tread, into the hearts and minds of psychopaths and killers, and the shadowy spaces of his own soul.