Fritz Lang directed this 1953 film noir, which would lead one to expect that it would be at minimum pretty good. I think it's way better than that, one of the best of its type, although it isn't my favorite (my favorite so far is Out of the Past--see this post). Glenn Ford stars as an honest cop whose investigation of a suicide leads him to a web of big-city corruption. That sounds tired, I know, but the way it works out is not. Gloria Grahame, who played Vi in It's A Wonderful Life, is a gangster's girlfriend who, in a departure from the typical, proves to be quite the opposite of a femme fatale, except...well, no, that would be a spoiler. Anyway t's a very poignant role, and performance.
This poster is pretty much useless as guide to the movie. It's funny how many crime/detective novels and films are called "The Big" something or other. In this case it refers to the heat which is going to come down on the crime syndicate if/when certain information is revealed.