It is notable for featuring four iconic horror film stars (Vincent Price, Christopher Lee, Peter Cushing and John Carradine) together for the first[2] and only time.

[3] The screenplay by Michael Armstrong is based on the 1913 novel Seven Keys to Baldpate by Earl Derr Biggers,[2] which was also adapted into a famous play that gave birth in turn to several films.

As the stormy night progresses, more people come to the mansion, including Lord Grisbane's sons Lionel and Sebastian, Magee's publisher's secretary, Mary Norton, and Corrigan, a potential buyer of the property.

After much coaxing, the Grisbanes reveal that they are here to release their brother, Roderick, who was imprisoned in his room for 40 years because he seduced a village girl when he was 14 and killed her when he found out she was pregnant.

Soon, Diana and Andrew, a young couple who Magee met at the railway station, arrive seeking shelter from the storm.

As the couple walk out of the publisher's office and pass by a pub down the hall in the same building, Magee notices that the waiter attending the gentlemen in the bar looks exactly like Lionel Grisbane.

"[1] In a review of the Blu-ray release, Chris Coffel of Bloody Disgusting compared it to a Hammer horror film and said "It’s not the best movie for any of the four stars involved.