An alien agent from the distant planet Davana is sent to Earth via a high-tech matter transporter. There, he terrorizes Southern California in an attempt to acquire blood for his dying race, the result of a devastating nuclear war.
The opening shot is of a young couple (Gail Ganley and Ralph Reed) in a sports car necking. She excuses herself and the boy drives off. The girl is approached by a man carrying a silver briefcase. He removes his sunglasses and she screams and collapses on the lawn. The man removes a rubber hose and needle and attaches it to her neck and empties her blood into vials in his case. We get a close up his eyes and they are just milky white orbs. Title and credits run over pen and ink drawings.Note: Paul Birch left the picture before principle photography was completed. Lyle Latell completed his scenes.A Cadillac pulls up to a hospital, on the wrong side of the road, next to a fireplug, and in front of a no parking sign. Paul Johnson (Paul Birch) enters the hospital. He is greeted by Nurse Nadine Storey (Beverly Garland). He has come for a transfusion of blood. He refuses a blood test, which both the doctor and nurse find incomprehensible. Dr. F.W. Rochelle (William Roerick) comes out of his office and invites Mr. Johnson in. Dr. Rochelle explains no doctor on earth would do a transfusion without knowing the blood type of a patient. Johnson walks over to the lab bench, grabs a scalpel and cuts his wrist. There is no bleeding. Johnson explains to the doctor that it will bleed later. Johnson telepathically communicates with Rochelle. He agrees to the blood test, but swears the doctor to secrecy. Rochelle begins studying Johnson's blood as Nadine gives him his transfusion. Johnson asks Nadine to work for him. She agrees only if the doctor approves, which he does. Rochelle's orders are for a daily infusion of 500 cc of type "O" every night.A motorcycle police officer, Harry Sherbourne (Morgan Jones) is making his rounds when he sees Johnson's car. He prepares to write a ticket for multiple violations when Nadine and Johnson exit the hospital. Nadine and Harry know each other and she convinces him not to write up Mr. Johnson. She explains Johnson is very sick, so Harry agrees to escort Johnson home. At Johnson's residence, he is greeted at the door by his chauffer and butler, Jeremy Perrin (Jonathan Haze). Johnson tells Jeremy to prepare a room for the nurse. Johnson goes to the kitchen and removes several vials of blood and places them in the refrigerator. When finished, he goes down into the basement. Jeremy enters the kitchen, which he was expressly told not to do. He pulls out a clear cylinder and as he tries to open it, he is frozen by Johnson telepathically. Johnson tells Jeremy if he spies on him again he "will be eliminated."Nadine drives her car to the Johnson residence. She is carrying a single suitcase. Before she can ring the doorbell, Jeremy greets her. He makes a clumsy pass and she rebuffs him. He finds her attractive, she is disinterested. She enters the living room and apologizes for her late arrival. She explains to Johnson that she had to clean out her desk at the hospital. Johnson escorts Nadine to her room upstairs. He departs but locks her door from the outside. She objects and tells Johnson if her door is to be locked, she'd prefer to do it herself. Johnson returns to the living room, which seems to double as a bedroom. He retrieves a communication device and calls his home planet of Davanna. The closet has been converted into a matter transporter. A floating head, "the courier" (January Boleslavsky) communicates with Johnson telepathically and relays the current and dire conditions on his home world. We learn that the earth is under study from these aliens like Johnson. They need huge quantities of blood as a result of war and radioactivity. Johnson is given his marching orders in six phases:
1) Study humans.
2) Return more blood home.
3) A live human for research to be teleported to Davanna.
4) Johnson is Phase 4–Earth blood transfusions.
5) If Earth blood keeps him alive–conquest, subjugation and pasturing of the Earth's population.
6) If Johnson dies, destroy the Earth.The next morning Jeremy prepares breakfast for Johnson. Under his jacket he carries a gun. He delivers Johnson his breakfast. Johnson tells Jeremy to prepare the car for a trip to the Public Library. Johnson does not eat solid food. He adds a pill to water, which turns the liquid black, and consumes it. Jeremy brings Nadine her breakfast. He tells her he gets paid $300 a week for practically no work. Nadine takes Johnson's temperature. Nadine has no further duties until evening, so she decides to use the swimming pool.The doorbell rings. Since Jeremy is occupied, Johnson answers it himself and finds a vacuum cleaner salesman, Joe Piper (Dick Miller). Joe turns on the high pressure during the demo. When he mentions the cellar, Johnson becomes interested. He invites him in and escorts him to the cellar. There the boiler or furnace is stoked up and glowing. Joe sets up his equipment and comments about the dirt in the drain pipe. Johnson removes his sunglasses and when Joe looks at him he does a double take, screams and falls back dead. Johnson has his suitcase ready and drains the salesman's blood. When he is done he stuffs the body into the furnace.Jeremy is driving Johnson to the library. Along the way he encounters three winos. When Johnson asks about the "three gentlemen", Jeremy tells him they are just bums. Johnson mumbles, "Phase 2." He tells Jeremy to invite all three to dinner tonight. Jeremy is shocked and horrified, but has learned to just follow strange orders by the boss.Harry Sherbourne is driving and notices Dr. Rochelle sitting on a bus bench. His car is in the shop, so Harry offers him a lift. They are both heading to the Johnson residence anyway. By the pool, Nadine notices smoke rising from the chimney. It is a warm day and no one should be using a fireplace or furnace. She walks down into the cellar to investigate. She is carrying her bathing cap. Before she can open the furnace door she notices a large number of Erlenmeyer Flasks. She puts her cap down and picks up an empty flask. She removes the stopper and sniffs. She grimaces from an apparent bad smell. She again approaches the furnace, but before she can open it, she hears a car horn. She puts the empty flask down on a small table next to the stairs and exits the cellar.Harry and Dr. Rochelle arrive. Just as they exit their car, Jeremy pulls up in the Cadillac. Harry recognizes Jeremy, a frequent guest of the police. Nadine takes Harry and Dr. Rochelle into the house. Dr. Rochelle goes into the living room with Johnson. He tells him, "Your blood is different from any I ever studied in my entire career." He has a low red blood count and his blood appears to be "evaporating" for lack of a better description. Dr. Rochelle thinks it might be a plague and that time is critical. Johnson tells Jeremy to tell Harry to return Dr. Rochelle to his work, and to go to the park and "collect my dinner guests." Nadine thinks Jeremy swiped her bathing cap because she can't find it. Johnson is in the cellar churning the ashes in the furnace and stoking it up for later. He picks up her bathing cap. Jeremy collects the winos and returns them to the house. They are in the basement with Johnson drinking when Johnson removes his sunglasses and fries their brains. Johnson loads numerous vials of blood into a trunk and tells Jeremy to move it to the living room. Harry and Nadine walk back to the Johnson residence from a date. Harry warns Nadine to be careful. He refers to the pair in the house as "a creep and a two-bit crook." "I don't like the feel of this place." Johnson communicates with Davanna. The trunk is teleported. The next item on the agenda is a live subject.At police headquarters, Sgt. George Walton (Roy Engel) is on the phone and discussing a case involving "neck punctures." Harry enters the room. So far thirteen people have been killed with the same M.O. He goes on to explain that he has some kind of device that burns out the eyes and brains of his victims, and then he drains them of their blood. He notes that the missing person rate has gone up sharply.Nadine gives Johnson his evening transfusion. He casually asks her if she has any relatives. She tells him, "Just an Aunt in Detroit who raised me." After his transfusion Johnson goes on the prowl for a human subject to transport to Davanna. He spots an oriental man (Harold Fong). He telepathically directs the man to follow him home. He is told by the courier that things are devolving into anarchy on Davanna. Johnson reports that he won't know if the treatments are working for three more days. The Chinese man is teleported to Davanna.The next morning Jeremy enters the kitchen with Johnson's untouched breakfast. Nadine examines it. She notices the black water and its vile chemical smell. Jeremy volunteers other odd behavior like the three winos and the Chinese man arriving and never leaving. She decides to take the "water" to a lab and have it analyzed. Johnson and Jeremy are preparing to drive into town. Johnson hands Jeremy Nadine's bathing cap. Nadine brings the sample to Dr. Rochelle. She gets a call from Harry. Dr. Rochelle's new nurse, Joanne (Tamar Cooper), brings in a bottle of canine blood infected with rabies. She labels it and puts it in the refrigerator. Nadine and Harry make a dinner date for 6:00 p.m. She invites Dr. Rochelle to join them later at the restaurant with the test results.Johnson is on the street when he recognizes a woman from Davanna (Anna Lee Carroll). She too wears sunglasses. They stop at a magazine stand and telepathically communicate. She explains she came through the transporter at Johnson's home because anarchy reigns back home. He tells her she can help him with his work. She also tells him that transport back through the beam is impossible. The Chinese man was crushed when he arrived on Davanna. She finally tells Johnson she needs blood. While Johnson takes the woman to Dr. Rochelle's lab, Dr. Rochelle joins Harry and Nadine for dinner. Dr. Rochelle tells Nadine the black liquid is a complete food. Nadine finally reveals the source–Johnson. Rochelle blanches, then changes the subject and will not discuss Johnson any further. Back at the hospital, Johnson accidently gives his companion the rabid dog blood for her transfusion. She complains of feeling strangely, but is assured that is normal. She walks to her hotel room, but doubles back to the hospital and collapses on the stoop. Dr. Rochelle was returning to his lab and sees the woman. He has the nurse help him get the woman to his office. He removes her sunglasses and she opens her eyes. Like Johnson's they are milky white orbs.Johnson goes to pick up his car. The attendant (Tom Graeff) leads him to his car. Johnson directs him into the car, "I must have a second live specimen." A customer honks his horn for the attendant and the spell Johnson has over him is broken. The attendant bolts from Johnson's car. Johnson gives chase and kills him.Harry calls Nadine at Johnson's house. He tells her a woman died and that she had no eyes and wore the same sunglasses as Johnson. He tells her Johnson is dangerous and wants her to leave. Unwisely, Nadine ignores the advise and stays to do a little investigating with Jeremy. They search the house. They discover the communication device and the transporter in the closet. Jeremy discovers a skull in the furnace. Johnson arrives home. The phone rings and Nadine answers. She is unaware Johnson is home and picks up the downstairs phone and listens to her conversation with Dr. Rochelle about the Davanna woman. Johnson tells Nadine to remain in her room, and then hangs up the other phone. Johnson kills Jeremy then runs upstairs to kill Nadine. She won't look at him and employs a piercing scream to escape. Johnson is especially sensitive to loud noises. She bolts from the house. He gives chase in his car. Telepathically he tells her he is going to destroy Dr. Rochelle. He goes to the kitchen, removes a glass cylinder that Jeremy was examining days before. He reanimates a creature that resembles a cross between a crab and an umbrella.Dr. Rochelle is examining the blood sample while the umbrella creature seeks it prey. It makes a noise like a guinea pig. It enters Rochelle's office through an open window. It drops down and engulfs the doctor's head. The doctor briefly struggles, collapses on his lab bench and bleeds out.Johnson drives to Nadine, following her mind signal. Nadine calls Harry and tells him Johnson is after her. Johnson chases her in the car and on foot through a park. Harry and Simmons (Pat Flynn) try to find Johnson and Nadine on their motorcycles. Nadine tires and is finally controlled by Johnson. She is to be the next human specimen to be sent through the transporter. He tells her to return to the house and step into the beam and transport herself to Davanna. Johnson kills Simmons. Johnson targets Harry when he chases his car on the motorcycle. Harry uses his siren and causes Johnson to roll the car, breaking the spell on Nadine. She sobs while standing in the transporter.Harry and Nadine are standing next to a headstone. On it is written, "Here lies a man who was not of this earth." They exchange small talk at the graveside. We close with a lone figure of a man approaching, dressed like Johnson and wearing sunglasses.