When the newspaper runs a promotional contest awarding fifty dollars for the best story written by a high school journalitst, Bostwick, the city editor, decides to wash his hands of the kids by assigning them to cover trivial topics. Undaunted, student reporter Nancy Drew, the daughter of District Attorney Carson Drew, overhears the staff discussing the Lambert murder hearing and decides to cover the trial herself. At the courthouse, Nancy sits next to a man with a cauliflower ear and listens intently as Eula Denning, the murder victim's ward, is accused of poisoning Kate Lambert for the inheritance money. Eula's only defense is that the fingerprints on a missing tin of poison do not match hers, and after the court is adjourned with Eula's conviction, the man with the cauliflower ear speeds off in his car, smashing Nancy's car fender in the process. Nancy trails the man to the Lambert estate, and when Bostwick refuses to follow up on her lead, she decides to undertake her own investigation. Tricking her boyfriend, Ted Nickerson, into helping her, Nancy tracks down the tin, only to have it stolen by the girlfriend of the man with the strange ear. Nancy discovers that the man is a boxer named Soxie Anthens, and traces his girlfriend, Bonnie Lucas, to Miles Lambert, the nephew of the slain woman. Learning that Miles will inherit the Lambert fortune if Eula is convicted, Nancy suspects him of the murder and sets a trap by printing a false story that the missing tin has been found. As Lambert races to Soxie's room to claim the tin, Nancy, Ted and Sergeant Entwhistle of the police department record his confession with a hidden tape recorder, thus bringing the real killer to justice.