Santo in The Witches Attack aka Santo en Atacan las brujas opens with a dream sequence/vision from a woman named Ofelia. Her visions include: Satan, Santo, stuffed animals, live lizards, amongst other strange things. We then cut to Santo entering an old building and fights two masked men before being subdued. He’s tied to a table, and Ofelia is chained to another. Queen of the witches Mayra is invoked by her followers. Mayra promises to sacrifice Santo and Ofelia to their master, Satan – complete with furry face and horns! Santo breaks free, and casts the shadow of a cross with his body, arms outstretched. The witches flee. Suddenly, Ofelia wakes up.
She has been having this same dream repeatedly. Ofelia tells her boyfriend Arturo that, after her parents died, Elisa Cárdenas, their former secretary, came to her with news of their will: Ofelia has to live in the old house for one year in order to inherit. Arturo tells her that the masked hero of her dream really exists: El Santo.
Arturo discusses the case with Santo; the real Elisa Cárdenas died 15 years earlier, and her place has been taken by a witch. But why? Santo investigates the old house, and is attacked by some of the henchmen. He inadvertently makes the sign of the cross and they flee. As he leaves, Santo picks up an attractive young woman in his car. He doesn’t know it is Medusa, one of Mayra’s assistants. Medusa leads him to another old house; she keeps disappearing and reappearing, leading Santo on. In the bedroom, she suddenly shows up wearing a sparkly bikini. Santo says to himself, “I’m the subject of an infernal seduction.” Instead of kissing Medusa, he pushes her away: “Go back to the shadows from whence you came!” Kicking down the door, Santo escapes.
Santo and Arturo return to the house, which is now filled with cobwebs. Entering the room with the shattered door, they find a coffin instead of a bed. Arturo tells Santo that the witches can only be beaten by the sign of the cross and daylight; Santo doesn’t understand why he managed to scare them off. As they leave, Arturo sees visions in the road and wrecks. Mayra’s henchmen kidnap the unconscious Arturo. Mayra mentally orders Ofelia to remove the cross she wears, and Ofelia is also captured.
In the witches’ dungeon, a hypnotized Arturo and the three male henchmen subdue Santo when he arrives. Santo and Ofelia are to be sacrificed to Satan at a particular moment, but Mayra doesn’t want to wait; however, Santo leaps up, grabs several torches.The witches all turn into bats and fly away. Later, Satan tells Mayra that she must sacrifice Santo and Ofelia, or he’ll be mad.
Time out for a wrestling match. Oddly enough, this appears to be taken from an earlier Santo film, since Augusto Benedico can be seen in Santo’s corner, and his opponent is Fernando Osés, one of the witches’ henchmen, but apparently playing a different role here!
Santo is asleep and is hypnotized by Mayra. Medusa hypnotizes Ofelia–asleep in the next room–by wiggling her long fingernails. Arturo enters and carries her away. When Santo wakes up, he speeds to witch headquarters, but the dungeon is empty. The next night, Mayra sends a big spider to bite Santo, but he stomps on it. Ofelia shows up, says she escaped, but they have to save Arturo. They go to the old house again. Suddenly, Ofelia changes to Mayra– she tricked Santo!
Santo goes in, nearly falls into a pit full of spikes (two of the henchmen stomp on his fingers but he won’t let go; finally, one of the henchmen falls in and is impaled). He’s tied up and put on a table for the sacrifice, but–just like he did twice before (well, once was in Ofelia’s dream)–he breaks loose and runs out. He comes back with a big wooden cross that he waves like a railway crossing sign, which makes the witches burst into flame (one of these is a dummy that catches fire, the rest are “burned” via superimpositions). Mayra stabs Arturo with her ceremonial dagger before she burns up, but he’s magically healed. This is explained by Santo, he notes that the evil the witches caused vanishes when they die. As Ofelia and Arturo clinch, Santo hops into his sports car and leaves.