Set in Spain 200 years ago, the story begins with a beggar (Richard Wordsworth of THE QUATERMASS XPERIMENT fame) displeasing a spiteful, cruel marquess, who has the homeless man thrown into his dungeon, where he is forgotten.

Years later the mute daughter of the dungeon’s jailer (Yvonne Romain) rejects the advances of the now-decrepit (and scabby) Marquess and she too is tossed into the dungeon, where the mad beggar rapes her. After being freed from the dungeon she kills the Marquess, flees the mansion and is taken in by a kindly scholar, Don Alfredo Corledo. Here she dies as she gives birth to a son on Christmas Day (which is considered extremely unlucky).

The boy is named Leon and he is raised by Don Corledo. As he grows older it becomes apparent that the child is affected by the full moon. Sheep are savaged, but Don Corledo manages to keep the boy’s traits a secret, with a local dog being blamed for the killings.

Years pass, he reaches manhood and Leon (Reed) begins transforming into a werewolf again, with only the love of Cristina, a rich vintner’s daughter, able to suppress his primal imperative to become a man-wolf during the full moon. Unfortunately, Leon is separated from Cristina and jailed, where he transforms once more, goes on a rampage and is hunted by townsfolk across rooftops, until he finally meets his fate at the hands of a loved one.

As you can see by this plot overview, the movie really delves deeply into what it takes for Leon to become a werwolf: being conceived by a mute woman who was raped by an animal-like madman, being born of Christmas Day, being separated from the one true love who can stop him from transforming, etc. Unfortunately, this means that the movie takes a very long time before we reach the point where we see Reed become a slavering lycanthrope…

It is worth the wait, though, as Hammer Films’ only werewolf movie stands out primarily because of Oliver Reed’s central performance: his eyes, even under the makeup, exude menace. Roy Ashton’s werewolf design is striking, using Reed’s masculinity and solid frame to make the grey-furred, red-eyed, sharp-toothed wolf man a physically impressive presence.

Ultimately, the overly prolonged origin section of the tale does lesson the impact of the film (which wasn’t as successful as Hammer’s previous horror films when it was released), but it still has much to recommend it, including the art direction and the seriousness with which Hammer treats the subject matter.