The heirs of the dying owner of a valuable radium mine are being murdered as a mining engineer tries to uncover the killer and clear his cousin's name.The heirs of the dying owner of a valuable radium mine are being murdered as a mining engineer tries to uncover the killer and clear his cousin's name.The heirs of the dying owner of a valuable radium mine are being murdered as a mining engineer tries to uncover the killer and clear his cousin's name.