The Hideous Sun Demon

When research scientist Dr. Gilbert McKenna falls unconscious after accidentally being exposed to radiation during an experiment with a new radioactive isotope, he is rushed to a nearby hospital. Attending physician Dr. Stern is surprised to find that Gil shows no signs of burns typical to a five-minute exposure to radiation and informs Gil's co-workers, lab assistant Ann Lansing and scientist Dr. Buckell, that he will keep the patient for several days of observation. Later, Gil is taken to the solarium to receive the sun's healing rays, but while he naps, the sun's rays metamorphose Gil into a scaled creature, horrifying the other patients. Seeing his own skin, Gil flees to the bathroom to confront his new appearance. Later, Stern explains Gil's affliction to Lansing and Buckell: Humans have evolved from a chain of living beings beginning with one-celled organisms that progressed into fish, amphibians, reptiles, mammals and finally humans. Stern assumes that the radiation poisoning has caused a reversal of evolution changing Gil into a prehistoric amphibian and that the catalyst for the regression is sunlight. Stern suggests that Gil can control his symptoms by staying in the dark and remaining in the hospital, but admits that the patient cannot be held against his will. Although Gil has resumed his normal appearance, he has become mentally unstable. Notifying Lansing of his resignation, Gil drives his convertible to his large manor in an isolated coastal region where he drinks himself into a stupor. After hours of aimlessly walking the grounds, Gil drives to a bar where he finds sultry piano player Trudy Osborne singing. Removing his sunglasses in the darkened bar, Gil meets Trudy's eyes in a romantic glance, but he soon leaves and recklessly drives back to his house. Back at the research facility, Buckell receives word that noted radiation-poisoning specialist Dr. Hoffman has agreed to help Gil and plans on arriving in the area within a few days. Because Gil has disconnected his phone, Lansing offers to drive to the manor to deliver Hoffman's letter. After studies about radiation poisoning offer no leads on solving Gil's own particular symptoms, he walks to the ocean bluffs to commit suicide, but the laughter from children playing nearby softens his resolve. Instead, Gil returns to the bar where Trudy joins him for a drink and comments that the evening is not over because it is "never late until the sun comes up." Although Gil is disturbed by the comment, his loneliness draws him closer to Trudy. When bar patron George insinuates that he has purchased Trudy's company for the evening and she rebuffs him, Gil defends her decision, causing a fistfight between the men. After knocking George to the ground, Gil flees with Trudy into the night in his convertible. Later that evening, after they kiss while walking the shoreline, they make love, falling asleep in the sand until the morning light awakens Gil. Realizing the sun's rays will cause him to become the amphibious monster, Gil speeds away in his car leaving Trudy stranded on the beach. Arriving at the house, Gil runs in but not before the transformation occurs. Meanwhile, Lansing arrives and seeing the cellar door ajar, bravely opens it to find Gil cowering in a corner, physically recovered from the transformation but in a state of shock. Gil is at first uninterested in seeing Hoffman because he believes he is "beyond help," but Lansing's sobbing pleas convince him to see the doctor. During his examination, Hoffman orders Gil to remain in the house at all times for precaution until he can return with help. Alone in the house, Gil's restless sleep leads him to return to the bar, where George and his thugs, prompted by Trudy's story about Gil's abandoning her, beat Gil almost unconscious. Fearing Gil will die if left unattended, Trudy takes him to her apartment where he sleeps until morning. After Gil asks to remain there until the evening, explaining he has a reaction to the sun, George arrives and, seeing Gil, forces him at gunpoint out into the daylight, causing the transformation to occur. Infuriated by George's threats, the creature strangles him to death, then runs into the hills, frightening children and brutally killing a dog in his path. Returning to the house, the creature finds Hoffman, Lansing and Buckell waiting there and returns to his normal human state. When Gil admits to the murder, others assure him that he acted in self-defense, but when the police arrive with an arrest warrant, a hysterical Gil races from the grounds in his car and accidentally hits a police officer. Later, Gil hides inside an oil field shack in a residential district, while police comb the area and set up roadblocks. Despite radio and newspapers reports that a killer is on the loose, young Suzy evades her mother's orders to remain inside the house and runs to her hideout, the oil field shack. Finding Gil there, Suzy offers to fetch him cookies and promises not to tell her mother about the strange man. However, when Suzy's mother sees her hoarding cookies, she questions Suzy until she admits that she has a new friend, a sick, hungry man. While the terrified mother calls the police, Suzy slips out the door to return to Gil. Her mother chases after her into the oil field where police cars are just arriving. Realizing Suzy is endangered by being with him, Gil carries the girl out of the shack into the sunlight where he lets her go and soon changes into the creature. In the ensuing police chase, the creature attacks another officer and then climbs the stairs to the top of a tall oil rig where another officer tries to apprehend him. As the creature begins to strangle him, the officer shoots him in his chest and Gil falls several stories to his death while Buckell, Hoffman and a sobbing Lansing watch in dismay.