Sylvia Welles hires Rip Conners to wire her apartment to tape conversations and use the result to make a spliced version as a joke to embarrass a friend. Richard Vanaman has been working on a financial plan for Sylvia to invest $250,000. After receiving a call from Sylvia, he delays going out with his wife to go to her apartment. While there he finds that she was bugging their conversation. He leaves in a huff but when he gets home, he realizes that a valuable gold coin he always carried with him was missing. Assuming it dropped out of his pocket, he returned to Wells' apartment only to find her dead. He was seen by the apartment building manager and now it's being reported in the newspapers that someone used the gold coin in a parking meter. Fearing that he may be arrested for murder, Richard Vanaman seeks help from Perry Mason. Richard is arrested and charged with murder but Perry soon realizes there are several people who may have had reason to commit murder.
—garykmcd