In a Welsh village, Cathy Evans delivers bread to the manor where Professor Mathers is staying. The housekeeper, Mrs. Ives, doesn't answer when Cathy knocks so the girls goes inside and looks around for someone. She finds Mathers in his lab and he asks what she's doing there. Cathy introduces herself and explains that she brought bread for the house. Mathers eats a piece of the bread and pays her, and explains that he's a professor of genetics. His evolved ape, Darwin, drops down from a bookshelf and eats some of the bread. Mathers has Darwin file his papers and the ape goes to obey, and explains that he evolved Darwin. She asks if he can do the same thing to people, and says that there's someone that she'd like to be smart for. Cathy explains that she doesn't have any parents, and Mathers asks to take a blood sample from her. The girl agrees and the professor takes her blood.
Cathy returns to the village and her sister Gert discovers that Cathy didn't bring back the correct change. She accuses her younger sister of stealing, and Gert grabs her. Two miners, Wilt Morgan and Gwyllm Griffiths, come in and Wilt comes to Cathy's help. When Wilt tries to get a kiss from Cathy, Gwyllm shoves him back. Cathy thanks him for his assistance, and Gwyllm offers to walk with Cathy to deliver more bread to Mathers. As they go, Gwyllm says that the foreman told him that he's spreading discontent among the miners because he thinks that he's too good for the job. Cathy invites him to come in with him, and Gwyllm agrees. He says that he'd like to turn his back on the entire town and get away from the stupidity and the mine. Gwyllm talks about how he'd like to see the entire town destroyed, and Cathy assures him that he's smarter than the others. He figures that he just needs one lucky break: a job where he could show them how smart he is. Mathers comes out and looks at Gwyllm, and then goes back inside. Cathy suggests that Gwyllm ask Mathers for a job, but Gwyllm tells her not to be ridiculous.
In the lab, Darwin takes apart a piece of equipment. Mrs. Ives comes in and says that Cathy is there. The housekeeper lets her in, and Mathers tells her that her blood is the wrong type. She calls Gwyllm in, and he says that he's come to apply for the job of assistant. Mathers describes his work and asks if Gwyllm is familiar with solid-state electronics and office work. He says that Gwyllm is best suited to being a miner. Cathy asks Mathers if he could evolve Gwyllm, and Mathers explains that he's trying to speed up the slow process of evolution. He suggests that he might raise a man past the point of violence, and Gwyllm asks him to do it with him. Mathers warns that it could be dangerous, but Gwyllm would rather take the risk than work in the mines for the rest of his life. Mathers calls Mrs. Ives in and tells her to clean Gwyllm up.
Once Gwyllm is cleaned up, he looks out the window of his new room at the village. He goes to the lab and Mathers takes a blood sample. The professor confirms that Gwyllm has the right blood type, and then uses selective wavelengths to stimulate the stronger genes in Gwyllm's body, advancing his evolution. He shows Gwyllm the lever that controls the forward and backward process of evolution, and Gwyllm enters the bombardment chamber. Mathers advances Gwyllm's evolution 20,000 and opens the chamber. Gwyllm's head has grown and the stub of a sixth finger has appeared on each hand. He can read Mathers' mind, and says that Mathers is praying that his experiment will be a blessing rather than a curse. He reads Mathers' thoughts about how he created a nuclear bomb and hopes that he will be forgiven one day, and he is trying to evolve mankind so war is no longer part of civilization.
Later, Mrs. Ives brings supper for Mathers and Gwyllm. Mathers tells her to leave it outside, and she does so before going back to the kitchen. The professor tells Gwyllm that it's best that Mrs. Ives not see him yet, and admits that he wasn't expecting a physical mutation. He explains that Darwin didn't belong to a species that evolved into man, so he didn't change form. Mathers suggests that Gwyllm will eventually develop a sixth finger for increased dexterity. Gwyllm talks about how it's a high cost to pay for power over other men, and reads Mathers' misgivings. As he stares at Darwin, Gwyllm looks at Mathers in the hand mirror he's using to examine himself.
In the morning, Mrs. Ives comes back to get the dinner plates and discovers that the food is uneaten. She calls through the lab door and asks if Mathers is okay, and he tells her to take the tray away. in the lab, Gwyllm completes an IQ test and Mathers says that they're not developed enough to measure Gwyllm's new intelligence. Frustrated, Gwyllm says that he requires knowledge and orders Mathers to bring him all of his books before storming out.
Later, Cathy delivers bread. She asks about Gwyllm, and Mrs. Ives says that something peculiar is going on in the lab. The housekeeper takes Cathy to Gwyllm's room and says that Cathy is there, and Gwyllm orders them to go away. Cathy figures that Gwyllm doesn't want her to interrupt his studies and walks off, while Gwyllm pours through Mathers' books. He finds a book of sheet music and studies it intently.
In the village tavern, Wilt is playing the accordion for Gert and flirting with her. Cathy comes in and Gert says that her face is pretty in a sad way. Gert orders Cathy to get to work, but Wilt blocks Cathy's way and asks about Gwyllm. Cathy says that he's trying to make himself better, but Wilt and Gert just laugh. When Wilt says that Cathy has finally spoken up to defend Gwyllm, she angrily shoves the accordion out of Wilt's hands and says that he can laugh at her but never Gwyllm.
Mathers hears piano music and goes to investigate. He finds Gwyllm playing the piano, and Gwyllm talks about how fear deprives humanity of the power of creation. Mathers says that he must get some sleep and Gwyllm says that he will stop playing soon.
Mathers is sleeping when Gwyllm comes in and wakes him, demanding more books. Gwyllm explains that he no longer has a need for sleep, and Mathers realize that Gwyllm has evolved further. The sixth finger has grown in, and Gwyllm explains that evolution is self-generating, and Gwyllm has no evolved one million years. He "reads" Mathers' thoughts that he's monstrous, and says that Mathers is as much a monster to him. Mathers insists that Gwyllm enter the chamber so he can set him back to a more human form. Gwyllm freezes him with his telekinesis and asks if Mathers would be willing to go back to an ape.
Later, Mrs. Ives brings Gwyllm more books and he tells her to leave them outside. She does so and starts to go, but then hides around the corner. When Gwyllm comes out, she screams in horror. Gwyllm tells her to stop, and then telekinetically stops her heart. Mathers comes out and confirms that she's dead, and Gwyllm says that it was in Mrs. Ives' mind to go to the village and bring the men back to Gwyllm, so he stopped her heart. He offers to bring Mrs. Ives back, and points out that she was no more advanced to him than a monkey. Gwyllm casually picks up the books and goes back into his room.
Mrs. Ives' body is taken to the village and prepared for burial. Gert figures that Gwyllm killed the housekeeper, and tells the village women that Mrs. Ives promised to get to the bottom of whatever was going on. She goes to tell the constable her suspicions. Cathy, overhearing, runs to the manor to warn Gwyllm. He telepathically knows that she's there and invites him into her room. Gwyllm knows that the constable has sent two men to investigate, and wonders why Cathy isn't afraid of him. She says that he's always been kind to her, and Gwyllm steps out of the shadows.
Scared, Cathy runs out and Mathers grabs her and takes her into the lab. She begs him to bring Gwyllm back to her the way that he was. Gwyllm leaves his room and says that he must set an example and destroy the entire village. He says that the human race has ceased to develop and will soon lose sight of the truth. Mathers takes out a gun, and Gwyllm telekinetically disarms him and then shoves him back. He then telekinetically opens the door and leaves. Cathy confirms that Mathers is okay, and he goes to the phone while Cathy realizes that the only thing left of her Gwyllm is his hatred of the village.
The two policemen pull up and Gwyllm steps out to confront them. He telekinetically disarms one and knocks him back, and says that their savageness must end. However, he suddenly stops and walks away. Mathers pulls up and confirms that the first policeman is okay, and the other one explains that Gwyllm changed his mind.
Gwyllm returns to the lab and tells Cathy that he evolved beyond the desire for power. He's reached the stage of evolution where the mind will become thought and no matter. Gwyllm tells Cathy that he needs her help to go forward, because she's the only one that he trusts. He sees that she's crying, and Cathy begs him to come back to her the way she was. Gwyllm tells her that she was the one who brought him out of the darkness, and now he needs her to help him achieve the ultimate.
Mathers drives back to the manor.
Gwyllm tells Cathy what to do and warns her not to push the lever backward because that will send him into his evolutionary past. Cathy opens the door to the bombardment chamber and then closes it when Gwyllm steps inside. She says that she can't let Gwyllm go and pushes the lever backward. Gwyllm's evolutionary advances reverse and then go back even further as he reverts to Neanderthal man. Realizing that she's gone too far, Cathy pushes the lever forward .
Cathy opens the door, revealing Gwyllm in his human form. He steps out and touches the tear on Cathy's cheek, and stares at it for a moment. As Mathers comes in, Gwyllm collapses and Cathy tells the professor that she brought Gwyllm back and thinks that he's glad.
Written by Gadfly on Feb 10, 2018