British horror icons Peter Cushing and Christopher Lee co-star in this fascinating bit of Victorian pseudo-scientific nonsense which will have you entertained until the very last scene. The bad news is that they share very little on screen time, in fact there isn't all that much Lee content at all. But that is my only gripe about this terrific horror thriller. If you want to see the two REALLY co-star go to their many Hammer classics or the brilliant 'Horror Express' from around the same period as this. Cushing plays a familiar role, Hildern, a scientist with good intentions who meddles with something he shouldn't have. He shares a home with his adult daughter, the sweet and innocent Penelope. She believes that her mother died many years before not realizing the truth, that she was a fun loving floozie who flipped out and spent many years in an asylum, run by Cushing's ambitious half-brother James (Lee). Hildern returns from an expedition from New Guinea with a mysterious skeleton of a giant creature which he believes predates man. On his arrival home he is greeted with the news that his insane wife has finally died. He still hides this knowledge from his daughter, fearing for her own mental well being. Hildern and his assistant experiment on the skeleton and he believes that it can unlock the secret of evil, which he theorizes can be innoculated against. When a hysterical Penelope finally stumbles across the truth about her mother, Hildern, with the best of intentions, tries the experimental anti-evil vaccine on her. This proves to have disastrous results, and matters are further complicated when James, who both envies and resents his more respected brother, gets wind of what is going on and plans to steal the skeleton for his own research. If you take all the "science" in this movie with a pinch of salt you'll find it to be one of the most enjoyable horror movies Cushing and Lee were ever involved in. A most underrated movie, highly recommended to all fans of late 60s/early 70s British horror.