In a large suburban house, a woman makes a phone call in a state of nervous desperation. Though her sister Bessy is to come right over, she is suddenly struck down by an unknown assailant. The sister that Edna had phoned is now in the office of Mr Keen to tell him the story of the murder, and now missing Edna. Mr Keen and Mike Clancey comfort her, as they go to make a search of the house.

At the house, a man pulls up, he turns out to be the real estate agent that rented the house to Edna. Together, they have a look around the place. A phone call comes in from the property owner, who is on the way over. As the man and his wife arrive, Mike has found the body of the strangled woman. The police are notified, and the couple share a superstition about the house. The relative they inherited it from had died in quicksand.

Mr Keen takes in all the odd events, but looks for a motive that he thinks will connect the past murders with this one. Is it all just coincidence, or is there something to actually tie it all together? Mr Keen has a look with Mike at the pool of quicksand. The previous murder of the rich relative hasn’t been very long ago. Did Edna discover a clue that got her killed?

The sound of gunshots draw Mike and Mr Keen away, and back towards the house. The shooter has gotten away, and Mr Keen finds the sister in the house. She is warned to leave as Mr Keen prepares to spring his trap to catch that vicious murderer. Mr Keen uses an important clue that he found earlier, and the killer is lured into the trap. Who is it? In dramatic fashion,complete with secret rooms, and sneaking around, Mr Keen confronts the killer, and the mystery is exposed, with all the details being told.