After losing his car to a ravine 27 year old American Encyclopedia salesman Jack Robinson (Pat Boone) finally arrives at the creepy home of his intended Cynthia Marley (Erica Rogers) and her peculiar family. The introductions begin on a downbeat note with news of the recent passing of cousin Creighton whose body lies in repose in an upstairs room. Shown to his room normally occupied by Cynthias cousin Cornwallis Marley (Dennis Price) Jack is greeted by a large tarantula in his bed. The arachnid belongs to Cornwallis uncle Percival (Jack Bligh) a man who’s rigged the doorbell to fire blank rounds to discourage unwanted visitors. After getting knocked cold from another quirky invention of the elder Marley Jack learns of the existence of Muldoon (Archie Duncan) the brother of vampire cousin Natalia (Andree Melly). Traumatized by a tribe of headhunters Muldoon has escaped from three asylums and now lives in a dungeon cell responsive only to Natalia. Percival is quite the master inventor. He’s come up with electricity moving pictures and sound recordings things Jack hasn’t the heart to tell him have long been a reality. With the presumption of murder now apparent in the death of Creighton Cornwallis having also met his demise and transportation to the police not available Jack is conducting an investigation of his own an investigation that leads to Grandpa Marley (Erik Chitty) the elderly patriarch of the Marley clan. Cynthia has let slip that the family has roughly 300000 pounds to its name certainly a motive in and of itself. Uncle Reginald (Valentine Dyall) believes that Jack himself may be the killer being as how he would have a shot at the Marley loot should he marry Cynthia. Percival has conveniently invented the horseless carriage a device capable of spiriting Jack and Cynthia to the police. Unfortunately he neglected to invent the brake… Extensive searches turn up no copyrights for this piece of crap.