Plot

Seventeen-year-old Isabella "Bella" Swan (Kristen Stewart) moves to Forks (from Phoenix), a small town near the Washington coast, to live with her father, Charlie (Billy Burke), after her mother Renee Dwyer (Sarah Clarke) is remarried to a minor league baseball player.

Forks is extremely cold, and the sun almost never shines in the county, and has a population of 3120 people. Charlie is the Chief of Police in the town. Logging trees is the biggest employment provider in the town. Bella used to visit for 2 weeks every summer, but it has been a while since she last came to town. Charlie gives Bella a lot of space, but their home has a single bathroom.

Bella is a romantic at heart and her deepest desire is to die for someone she loves. In the forests around Forks, a human figure is shown to be hunting a deer, without weapons.

Jacob Black (Taylor Lautner) is an old childhood friend of Bella and a member of the Quileute tribe. Jacob is the son of Billy Black (Gil Birmingham), who is confined to a wheelchair. Charlie and Billy are good friends. Charlie gifts Bella a pick-up truck as her homecoming present, which he bought from Billy after he rebuilt the engine. Jacob goes to school on the reservation.

Bella attends school in March, which is the middle of the semester. Bella does not like any kind of attention on herself and is not good at sports either. Bella is quickly befriended by many students at her new high school, but she is intrigued by the mysterious and aloof Cullen siblings Edward, Alice, Jasper, Rosalie, and Emmett. Bella sits next to Edward Cullen (Robert Pattinson) in biology class on her first day of school. When a fan blows air from behind Bella in Edward's direction, he literally covers his mouth and nose in disgust. This prompts Bella to think that she has bad body odor. Edward spends the whole class with his nose covered, and later Bella finds him in the administrative section of the school trying to change his class from biology to almost anything else. He is told that all classes are full, and he resigns himself to "endure it".

Bella's friends at the Forks school include Angela Weber (Christian Serratos), Mike Newton (Michael Welch), Jessica Stanley (Anna Kendrick), Tyler Crowley (Gregory Tyree Boyce) and Eric Yorkie (Justin Chon). Jessica educates Bella that she is the new "toy" at the school and hence is getting too much attention. She says that the Cullens are the foster kids of Mr and Mrs Cullen, who moved down from Alaska a few years ago. Jessica says that Cullens stick to themselves.

Bella planned to confront Edward, but he never showed to school for the next few days. Meanwhile, a man is chased and hunted at an empty factory by a group of humans. Charlie is called to Mason Country to investigate the death of a security guard at Grisham Mills by some kind of animal. It is the onset of winter, and it is starting to rain, which converts to ice on the cold ground.

Edward shows up in class and introduces himself very nicely to Bella. Edward says that he was out of town for a few days for personal reasons. Edward chuckles when he asks Bella if she likes the rain, and Bella responds that she responds poorly to any cold or wet thing. Edward reminds her that Forks is the wettest place in Continental US. Bella notices Edward's eyes which are golden brown. The last time she checked, they were black.

A few days later, Bella is nearly struck by a van (which belonged to Tyler) in the school parking lot. Edward inexplicably moves from several feet away and stops the vehicle with his hand without any harm coming to himself or Bella. Bella is treated by Dr Cullen at the hospital. Bella recounts how Edward was able to move really fast as he was nowhere near her. Bella sees Edward talking to Dr Cullen and Rosalie and defending his actions, saying that he could not let Bella die. Rosalie is concerned that 15 kids saw what Edward did. Edward later refuses to explain this act to Bella and warns her against befriending him. Bella sometimes wakes up in the middle of the night and finds Edward standing next to her bed, but he is gone as soon as she switches the lights on.

Eric and Mike both ask Bella out for prom, but she is too distracted to respond. She tells Mike that she is bad at dancing and has something that weekend already in Jacksonville. Bella asks Mike to go with Jessica. Edward asks Bella about Jacksonville, which means he heard her talk, even though he was nowhere close to her. So far, Edward had demonstrated high speed, extreme strength and exceptional hearing. Edward again approaches Bella and says that they should not be friends anymore. Bella retorts that he should have let the van crush her, rather than regret saving her. Edward says that Bella doesn't know anything, at which point they are interrupted by Alice and Jasper.

Bella accepts an invitation from Eric and friends to come with them to the La Push beach for surfing. Edward again approaches Bella at lunch and says that if she was smart, she would stay away from him. Edward says that he wants to be friends with her but knows that it is best if they are not. Bella theorizes that Edward is a superhero, but he says that he is the bad guy. Bella says that the bad guy act is only a mask to keep people away from him. Bella invites Edward to the beach.

Jacob meets Bella at the beach (which is on his reservation) and learns that she invited Edward who didn't show up. Jacob's friends retort that the Cullens don't come to the reservation. Jacob later tells Bella that Quileute's are supposed to be descended from wolves, and the Cullens are supposed to be descended from this rival, enemy clan. Jacob says that his great grandfather found the Cullens on his land, doing something. And a pact was made, for the Cullens to stay off the reservation in exchange for the Quileute to maintain their privacy and secret.

Charlie's friend Waylon (Ned Bellamy) is attacked by a human female, while he was working alone on his boat. The female is joined by 2 males who attack Waylon and kill him. Again, the death resembles that of an animal attack.

Jessica tells Bella at school that whenever the weather improves, the Cullens disappear. Bella goes to Port Angeles to buy a book on Quileute legends. It was late at night, and Bella was alone when she is attacked by punks. Suddenly, Edward arrives in his car and asks Bella to get in. he scares the punks away just by staring at them.

Edward later admits that he is very protective of Bella and was keeping an eye from a distance till she needed his help. He intervened when he could "hear" what the punks were thinking of doing to her. He also doesn't have dinner with Bella and says that he is on a "special diet". Edward admits that he can read every mind except Bella's. Edward drivers her home and says that he does not have the strength to stay away from her anymore. Bella touches Edward's hands and finds it to be very cold.

Charlie is distraught with Waylon's death and knows that the animal is gradually coming close to town. He gives Bella a pepper spray for her protection. After much research, Bella eventually discovers that the Quileute legends spoke of a "Cold one" which had parallels in several civilizations across the world. The creature was supposed to have great speed, strength, cold skinned, drank blood and immortal. Bella concludes that Edward is a vampire (he doesn't eat or drink anything and doesn't go out in sunlight), though he only consumes animal blood. Edward shows Bella that his skin sparkles like little diamonds in sunlight. Bella finds him beautiful, but Edward considers himself to be a killer. Bella continues to say that she trusts him, even though he says that he never wanted human blood more in his life. Edward reveals that the first time they met, he hated Bella for making him want her so badly.

The pair fall in love. He reveals that he has been a vampire since 1918, when he was dying of the Spanish Flu and Carlisle saved him by injecting him with Vampire venom. It takes a lot of restraint to taste human blood and then stop. Edward says that he does not want to be a monster. Edward tells Bella that there are other Vampires out there who killed Waylon. He says that all Vampires have a special ability. He can read minds and Alice can see the future.

Edward introduces Bella to his vampire family: Carlisle (Peter Facinelli) a compassionate 300-plus-year-old vampire who looks to be in his early 30s. He serves as the town's physician and is the father figure of the Cullen family, Esme (Elizabeth Rease) Carlisle's vampire wife, Alice (Ashley Greene) a vampire who can see the future based on decisions that people make, Jasper (Jackson Rathbone) a member of the Cullen family who can manipulate emotions. He is the newest member of the Cullen family, and thus has the most difficulty maintaining their lifestyle of feeding only on animals instead of humans, Emmett (Kellan Lutz) physically the strongest vampire of the family and Rosalie (Nikki Reed) Emmett's mate.

Their house is deep in the woods, secluded, but open and light. Rosalie is not happy that Bella knows their secret and says that this situation is dangerous for all of them. Edward's room had no bed, and he doesn't sleep. The family has made a wall display of all their graduation caps as a private joke.

Bella is in touch with Renee, who is enjoying life with her new husband. Meanwhile, Charlie investigates Waylon's death and finds a bare human footprint near the murder site. Edward visits Bella in her bedroom and says that he has been visiting her for the past couple of months to watch her sleep. They end up kissing, but Edward backs away as he doesn't want to lose control as it could lead to Bella being hurt. Bella introduces Edward to Charlie. Edward takes Bella to a family outing where they play baseball during a storm. The thunderclaps mask the noise of a ball being hit by a Vampire, which is very loud. The ball travels very far and the Vampires run after it to retrieve it.

Soon afterward, three nomadic vampires-James (Cam Gigandet) (the leader of a group of nomadic vampires. He is Victoria's mate and a gifted tracker, due to his unparalleled senses), Victoria (Rachelle Lefevre), and Laurent (Edi Gathegi) (the most civilized member of James' coven) arrive during the family's baseball game picnic. The blood vampires have red eyes, as opposed to the golden-brown eyes of the Cullens. James caught scent of Bella, and this caused a showdown, with the Cullens forcing the nomads to retreat.

James, a tracker vampire, is intrigued by Edward's protectiveness over a human and wants to hunt Bella for sport. Edward knows that his reaction turned Bella into a sport for James, and that James would never stop. Edward knows that for Bella to be safe, James would have to be ripped to pieces. Edward asks Bella to leave town, and Bella breaks Charlie's heart to hide the truth from him. She says that she is really bored, and that Charlie is not a good father and leaves the same evening.

Edward and his family risk their lives to protect her. Alice drives Bella south while the rest of the family wears Bella's clothes and try to lead James away from her. But James realizes that he is being misled and follows Bella's scent. Alice realizes that James has changed tracks and that he would lure Bella to a room full of mirrors. Bella identifies the room as the place where she took ballet lessons.

James tracks Bella to Phoenix, where she is hiding, and lures her into a trap by claiming he is holding her mother hostage. Bella leaves without telling Edward as that is what James instructed her to do. When Bella reaches the studio, she finds that James was only using videos of her mother to lure her.

James attacks Bella and bites her wrist, but Edward and the other Cullen family members arrive before he can kill her. James is destroyed (he is ripped to pieces and burned), and Edward sucks James' venom from Bella's wrist, preventing her from becoming a vampire.

The severely injured Bella is taken to a hospital. Renee meets Bella when she recovers consciousness. Bella says that she wants to stay in Forks. Edward wants Bella to go to Jacksonville with her mother, so he cannot hurt her anymore, but Bella refuses flatly.

Upon returning to Forks, Bella and Edward attend their school prom. Jacob meets Bella and says that Billy wants her to break up with Edward. While at the prom, Bella expresses her wish to become a vampire, which Edward refuses to grant. Victoria's secretly watches the pair dancing, plotting revenge for her lover James' death.