Jonathan "Jon" Lansdale (Michael Caine) is a comic illustrator whose marriage is on the rocks. He lives from the local Southern popularity of a super-hero he has been drawing for ten years, Mango. His wife Anne Lansdale (Andrea Marcovicci) doesn't seem too happy, as she gets bored living in a small town outside Reno and wants to go back to school. Jon throws out the idea of her going to live to New York. Several days go by, and one day, Anne tells Jon that she'd like to go back to studying in New York, she'd take their daughter Lizzie Lansdale (Mara Hobel), and he'd stay at their isolated country house. She admits it'd be an opportunity for both of them to do different things and meet different people. Jon gets angry, backs down from his idea, because he realizes that she's looking from a way out of the marriage, while he'd stay behind to pay the bills. They have this argument while they are driving on a village road. They've got a van in front of them, and another car behind. While the argument goes on and on, she honks and tries to overtake the van. At this moment, another van appears in the opposite lane. Jon signals for the car behind his to slow down and give them space to go back to the right lane, but it's too late. There is a traffic accident, resulting in Jon losing his right hand.A policeman (Tracey Walter) and blood-stained Anne look for the missing hand, but the high grass doesn't allow them to see clearly. At hospital, the doctor (Ed Marshall) prepares a gloved prosthetic hand for Jon, and tells him that much of his recovery will have to do with his effort; however, it's unlikely that he'd be able to earn his living as a comic artist anymore. To Lizzie's inquires, Jon answers that, if they had found the hand on the spot, they could have reattached it to his arm, but now, it's too late. Jon is condescendingly forgiving about Anne's part on his accident.Little by little, the Lansdales' life returns to normal... more or less. Anne insists on her idea of going to New York and living in a penthouse, but Jon won't allow it. He tries to draw with his left hand, but the quality is not there. The cat jumps out of the window. Jon goes back to the site of the accident: he can't find the hand, but he finds his seal ring from his university years. At this moment, the camera moves suggesting that something is lurking among the high grass. Jon has a weird moment when he confuses one of the shower taps with the hand. The moment passes and the illusion passes. Anne starts attending yoga classes, with attractive Bill Richamn (Nicholas Hormann) making Jon deeply jealous.Jon's editor, the pushing but pragmatic Karen Wagner (Rosemary Murphy) tries to convince him so that he forgets about drawing and concentrates on the script and the plot themselves. Norman Kaufman, the president of the company, insists in keeping Jon's character Mandro alive. A younger artist called David Maddow (Charles Fleischer) will do the drawings. This is the first time that we see the hand, all black and disgusting, covered with bugs, and the cinematic presentation turns to black and white. Anne thinks it's a way for them to secure their livelihood, as the comic sales will even improve because of a more modern approach to the stories. There is a meeting at Karen's office with Karen, Jon and Maddow, but Jon angrily rejects Maddow's innovative approach, talking about Mandro as though he were a real person with a real personality. Karen offers to make all necessary changes in each drawing, but Jon or the hand have blurred and painted over each drawing. Karen and Maddow stare at Jon in disbelief, as though he were crazy. When Jon leaves the office, he bumps onto a drunk bum (director Oliver Stone), who is also handicapped. The bum replies angrily to Jon. The scene turns in black and white as the hand strangles him. Jon comes back home as normal.Obviously, his is the end of the deal, causing Anne great anxiety, as they have no other financial resources. She doesn't want to explain her conversation with Bill, and Jon doesn't want to explain what went wrong in the meeting. She also feels disappointed that he doesn't want to go on with Dr. Silverman (John Stinson)'s psychotherapy sessions. Silverman thinks that he doesn't want to improve in order to keep Anne tied to him by sheer guilt. If Jon were able to fend for himself, she'd feel free to leave him and start a new life in New York with Lizzie in tow. Jon asks Lizzie whether she touched the drawings of Mandro in any way, and she says she didn't, although she admits she knew that her dad didn't like the drawings at all, and she says she didn't like the new version of Mandro either. Billy is around at the Lansdales' a lot.Luckily, the university of Saraville, in California, has offered Jon a job as a professor. Brian Ferguson (Bruce McGill) tells him that there is a cabin on the woods nearby which he can rent for cheap. For the time being, Anne and Lizzie will stay back in the village. Brian is the psychology professor, and he only cares about getting 15 students in his classroom. Jon's students, Billy Jenkins (Brian Kenneth Hume) and another girl (Lora Pearson) don't even have a favorite comic or comic hero. However, student Stella Roche (Annie McEnroe) is interested in the lessons and in Jon as a person.When Lizzie and Anne phone Jon, he doesn't remember much. Anne insists in staying behind until the Christmas season is over, as they have already paid the rent of their first country house. During the conversation, Jon has visions of the hand strangling Anne, especially when she tells him that both of them should try to meet new people on their own. That night, Jon can't sleep. There seems to be a leak in the shower and a tree breaks a window because of the storm and the wind. Jon finds his seal ring on top of his pillow.During teaching his next class, Jon uses Mandro as the example of the emotional evolution of a character. Later that evening, the eager Stella visits him on his cottage. They end up making love, and she doesn't seem bothered about Jon's prosthetic hand at all. Afterwards, Jon is worried because he sees a drawing of sexual nature but can't remember doing it. He asks Brian, and he tells him that it's very worrying because of the pornographic nature of the drawing: the hand is menacingly shagging a drawing of Stella. Brian thinks that the amnesia is the subconscious part of Jon's mind acting on its own. He could rape or murder during one of his trances. When Jon leaves the bar, he sees the hand moving under a piece of clothe within a shop, in black and white, and it attacks Jon.Jon calls Stella on at her workplace. Later on, she mentions that she'll go to LA for the Christmas, as she has friends there. Jon bought a present for Stella: it's a black negligee, wrapped in a luxurious gift box and a handwritten gift card. Stella is helping Jon to put up the Christmas tree, even though she hates those days; she adds that she has to go back to work, but that she'll come back to the cottage to make love to Jon. During that period of time, Jon decides to meet Brian at the local bar again. At the Last Chance Saloon, a country bar, the Country Bumpkins (Jack, Scott, Randy and Patrick Evans) are playing live. Brian tells him that he's going to LA, to a motel, to shag one of her students, wild Stella, whom Brian has been going after for quite some time.After work, Stella goes back to Jon's. The door is open, but he doesn't seem to be in. The hand is under the black negligée, and rapes and kills Stella.The next day, Jon goes to Reno to pick Lizzie and Anne up from the airport. Supposedly, they have arrived to California to stay. However, Jon soon realizes that Anne has no intention of staying put, as she hasn't even unpacked one of her two suitcases. Jon admits to have opened one of the letters which Billy sent to Anne. Anne says that she wants to move to New York because she has finally found a job there. She tries to calm him down saying that Lizzie likes Billy as a friend, but not as a father; so he will always have a place in their lives. Jon gets angry, and he keeps on seeing white flashes of light; he also becomes threatening and violent, telling her to leave, putting his remaining hand on top of her mouth to shut her up.She wants to leave, scared to death. Jon will lend her his car, but in the meantime Lizzie will stay with him. He notices that the hand has crawled to the back seat, but doesn't say anything. Anne realizes some disgusting stink, but Jon convinces her of dismissing it. Lizzie and Jon stay behind, playing Majong. Jon is stressed, and sweaty; he "sees" what must be happening to Anne at that moment - the hand crawling from behind Anne and trying to strangle her while she's driving in the rainy night. She has a car accident and the car blows up in flames with Anne inside. Lizzie notices that her father is confused, sweating like a pig, distracted. Lizzie gets happy when she hears somebody ringing the bell and runs to open up for her; her father thinks it's going to be some local police officers. However, it's Anne, who took long outside because the car stopped and she couldn't start it up again, so she had to phone for the towing truck. Jon had apparently imagined the entire event.Another day, at the same bar, Brian tells Jon that Stella didn't go to the date. That day, Jon states that he was traveling to Reno to pick his family up. Jon later admits that he had just seen her right before leaving for Reno. Brian drives drunk. The car finally starts up, and it's then when the hand strangles him in the rainy night. Blood splits everywhere.Anne will sleep at Jon's in the spare bedroom. Jon doesn't mind letting her go, but he wants Lizzie to stay with him. Anne looks a bit scared of Jon.In the middle of the night, Jon seems to be muttering something to himself. The hand attacks Anne who had just dozed off but realized that there was a kind of strange bulk under the sheets of her bedroom. Jon goes to Anne's bedroom and sees the hand leaving through the window. Lizzie wakes up because of the noise and thinks that Jon is hurting her mother. Anne looks in a coma, but alive. Lizzie calls the police while Jon goes out in the freezing rain in search of the hand. He follows it to the garage/barn nearby. The hand jumps at him from behind a heap of straw and tries to kill him. Jon stabs the hand but it crawls away, until it touches a tire and it explodes releasing a cloud of smoke. That hand strangles him, and he passes off.When Jon wakes up, there are flashlights pointing to him. The sheriff (Pat Corley) interrogates him softly. Lizzie is present while the conversation takes place, and a sergeant (Sparky Watt) is trying to calm her down. Jon thinks that the sheriff is staring at him. The sergeant notices an awfully nasty odour coming from the trunk of the car. The sheriff insists on opening it up. Jon gets frantic. The dead bodies of Brian and Stella are inside. (Jon remembers for the first time him killing Stella first and then Brian.)In the final scene at a local insane asylum, a psychologist (Viveca Lindfors) is trying to communicate with Jon. She wants him to remember and admit that it was him, not the hand, who killed all the victims. Jon says that the hand wants to kill her because it hates her. Suddenly, the hand (which apparently existed all along) appears from behind the psychiatrist and kills her. The now-deranged Jon laughs, releases himself from the chair straps and is free to leave the place, smiling.