Laura McNeal: What's the matter, won't the pieces fit together?
P.J. McNeal: Some of them, but they make the wrong picture.
Laura McNeal: Pieces never make the wrong picture. Maybe you're looking at them from the wrong angle.
Reporter P.J. McNeal (James Stewart) tries to match the pieces of a crime that was committed in Chicago in 1932. An advertisement - call Northside 777 - on the newspaper offering a reward for information on a murder had put him in contact with convicted Frank Wiecek (Richard Conte) and his mother who is working hard to get her son out of prison.
Stewart (who never looks too comfortable in his role) is impressed by the woman determination and decides to write about Wiecek case.
As the story progresses McNeal – who was sceptical about the case - gathers evidence that Wiecek is innocent and will fight to prove his innocence. We are told at the beginning of the movie that it is based on a true story. In fact the documentary style is present all along the film – it was popular at that time. Besides, Call Northside 777 was also filmed on location (Chicago) giving an air of realism to this interesting – though in some aspects dated – movie.