A man's pregnant second wife gets upset when he decides to go overseas to his young son, who may be dying of typhoid fever.

The police arrest a man climbing over the wall of a cemetery after midnight. He claims that he is being blackmailed and is following instructions he received by mail to leave $1000 on a certain grave. It turns out that he's not the only one who got a blackmail letter from the same person--calling himself "The Black Panther"--and it also turns out that all the recipients are connected to an opera company.

When a kindly priest is murdered while waiting at a street corner in a quiet Connecticut town, the citizens are horrified and demand action from the police. All of the witnesses identify John Waldron, a nervous out-of-towner, as the killer. District Attorney Henry Harvey is then put on the case and faces political opposition in his attempt to prove Waldron's innocence.