This series was produced in the late 60s and early 70s by the legendary horror film studio Hammer. 
In its 17 episodes, this series left a lasting impression on viewers because of it's opening sequence, a creepy roller coaster in an abandoned amusement park.

The series had a fantasy, science fiction and supernatural theme very similar to the American television series The Twilight Zone and dealt with normal people in everyday situations that found themselves having to experience something a bit out of the normal. 

It featured both British and American actors: American actors included George Maharis, Vera Miles, Barbara Bel Geddes, Patty Duke, Carol Lynley, Joseph Cotten, Stefanie Powers and Brandon deWilde, along with familiar British actors such as Dennis Waterman, Jane Asher, Kay Walsh, Roddy McDowall, Nanette Newman, Ann Bell and Tom Adams.

Never commerically released, transfered from VHS to DVD