Mrs. Castle appears as Marion Sterling, daughter of a big shipbuilder. Her father has just determined to turn his great plant over to the Government, when he is suddenly murdered. Marion is beloved by Hugo Smith, her father's partner, but she, herself, loves the young secretary, Gordon Brett. The tragic death of Mr. Sterling is brought about by choking, two arms appearing from behind the open front door during a rain storm. A detective named Barney Moffat is called in, and goes at once to work upon the case. His methods are unusual, and very effective. Gordon Brett is suspected of being the murderer, but the truth is brought out later in a dramatic way.