It was not theatrically released in Spain until 1975 due to problems involved in finding a distributor, although it was distributed in edited form on U.S. TV in 1974.

College professor Waldemar Daninsky travels to Tibet on an expedition and is bitten by a yeti, which causes him to become a werewolf.

Then she revives Waldemar's murdered ex-wife, who also becomes a werewolf (because she was fatally bitten by Daninsky), and forces the two werewolves to fight.

He is in turn shot to death by the doctor's young assistant Karin, a woman who loves him enough to end his torment.

He left the project early and was replaced by Jose Maria Zabalza, whom Naschy said was an alcoholic and a very uncouth person.

Due to the laziness of director Zabalza, this film wound up including a lot of stock footage from La Marca del Hombre Lobo (1968) to pad out its running time and a few carelessly mismatched werewolf scenes played by an anonoymous stunt double he hired without informing Naschy.