S04E17: The Case of the Wintry Wife

Inventor Walter Randall wants a divorce from his cold-blooded wife Laura in order to be with Phyllis Hudson. Laura decides to get back at Walter by blackmailing one of his assistants into building a bomb that will destroy Walter's underwater sounding invention. While checking on the bomb in the warehouse, Laura is discovered by Phyllis and takes advantage of the situation by knocking her rival out. Phyllis manages to survive the explosion but she is later charged with Laura's murder.