In this early '80s send-up of venerable horror clichés, Richard Benjamin and Paula Prentiss star as John and Mary, an ordinary couple who inherit a mysterious house from a deceased uncle. Along with kids Debbie (Kari Michaelsen) and Billy (Kevin Brando), they move into the musty mansion, unaware that vampire Waldemar (Jeffrey Tambor) and his wife are desperately seeking an ancient book housed within its walls. Soon, Billy finds the book and learns that opening it releases an assortment of scary creatures. John and Mary, however, refuse to believe Billy's tall tales, not even after Mary ends up with puncture marks in her neck and an aversion to normal food. Soon, a mer-man is stalking Debbie in the bathtub, relatives are disappearing and monsters have taken over the house. Help arrives in the form of the wise Van Helsing (Severn Darden) -- or does it? Saturday the 14th provided the directorial debut for veteran horror screenwriter Howard R. Cohen, who would return to the same territory with 1988's Saturday the 14th Strikes Back. Benjamin, who is married to Prentiss in real life, also appeared in the horror satire Love at First Bite.