Seventeen-year-old Bella Swan (Kristen Stewart) has decided to leave sunny Phoenix, Arizona, to spend some time with her father Charlie Swan (Billy Burke), the chief of police in the perpetually cloudy and rainy city of Forks, Washington, on the west coast of the Olympic Peninsula, so that her mother Renée (Sarah Clarke) and her minor league baseball-playing stepfather Phil Dwyer (Matt Bushell) can go on the road together for spring training and perhaps even move to Jacksonville, Florida.
Bella’s relationship with her father is cool, even though she hasn’t seen him inseveral years. When she arrives in Forks, he surprises her with the gift of a red pickup truck he purchased from his best friend, Billy Black (Gil Birmingham). Bella remembers making mudpies with Billy’s son Jacob (Taylor Lautner) and looks forward to having at least one friend at Forks High School, until Jacob reminds her that he is a Quileute Indian and goes to school on the Reservation. Not to worry. On her first day of school, Bella is befriended by Eric Yorkie (Justin Chon), the school’s “eyes and ears”, and he introduces her to some of the other students. Everything is looking cool so far.
Cool, that is, until she meets Edward Cullen (Robert Pattinson). Edward is one of five foster kids adopted by Dr Carlisle Cullen (Peter Facinelli) and his wife Esme (Elizabeth Reaser). There’s also Alice (Ashley Greene) and Emmett (Kellan Lutz) Cullen and the twins, Rosalie (Nikki Reed) and Jasper (Jackson Rathbone) Hale. From the moment Edward lays eyes on Bella, he can’t stop scowling at her. When Bella is assigned as Edward’s lab partner in Biology and he storms out the door when the bell rings, Bella is puzzled as to what she could have done to anger him. When she overhears him in the office attempting to transfer out of Biology, she decides to confront him and ask him what is his problem. However, she doesn’t get the chance because Edward is absent for the next several days. When Edward does return to school, he seems changed. He introduces himself to Bella and asks her about herself, her family, and whether or not she likes the cold, rainy climate in Forks. Bella notices that his eyes seem a different color than previously, and he answers awkwardly before walking away. Later that day, as Bella is about to get into her truck, another car careens out of control in the school parking lot. Within seconds, Edward has crossed the lot, pulled Bella out of the way, and seemingly stopped the car with his bare hand, leaving Bella more puzzled than before. When she tries to ask Edward how he did it, he simply chalks it up to an “adrenalin rush” and refuses to talk about it. Further, he says that they probably shouldn’t even be friends.
That doesn’t stop Bella from asking Edward to be her date when the kids decide to go surfing at La Push Beach on the Indian Reservation, but Edward doesn’t show. When the kids are joined on the beach by Jacob Black and two of his friends from the Reservation and they learn that Edward Cullen was supposed to be Bella’s date, one of Jacob’s friends remarks, “The Cullens don’t come here.” Later, Bella asks Jacob what was meant by that remark, and Jacob tells her of a Quileute legend that says the Quileutes are descended from wolves whereas the Cullens are descended from an enemy clan. The legend also goes that the Quileutes and the Cullens made a pact that required the Cullens to stay off Quileute land in exchange for the Quileutes keeping it secret what the Cullens really were. Bella googles Quileute legends and notices that there is a bookstore in Port Angeles that sells several books on Quileute legends, so she goes along with her new friends, Jessica Stanley (Anna Kendrick) and Angela Weber (Christian Serratos), when they decide to go shopping in Port Angeles for their prom dresses.
After purchasing her books, Bella heads to the restaurant where she planned to meet Jessica and Angela for dinner before heading back to Forks. Along the way, however, she is stopped by four guys with no good on their minds. Suddenly, Edward drives up, forces the guys to back off, and orders Bella to get into the car. When Edward and Bella finally join Jessica and Angela, the girls have already eaten. Edward offers to see that Bella gets some dinner and then to drive her back to Forks, so Jessica and Angela take off, giving Bella and Edward a chance to talk privately. Edward reveals that he was following Bella because he has developed very protective feelings towards her. He also lets it slip that he could read what was in the minds of those low-lifes and that he can read just about anyone’s mind…except for hers.
On the drive back to Forks, Bella accidentally touches Edward’s hand and is amazed at how cold it is. As they pass the Forks Police Department, they see several police cars, including that of Bella’s father, with their lights flashing. Dr Cullen’s car is also there, so Bella and Edward stop to see what’s happening. They learn from Carlisle that the body of Waylon Forge, a good friend of her father, was just found lying in a boat, dead from what looks like an animal attack, this being the second animal attack to happen near Forks. Later, after Bella has returned home with her father, she starts paging through the books she purchased and comes across a Quileute legend about “The Cold One.” Googling it, she learns that “The Cold One”, aka Apotamkin, is a fanged creature, described as undead, immortal, possessing incredible speed, strength, and cold skin. It is said to drink human blood and variously equated with other legends about vampires.
The next day, Bella confronts Edward with her findings. He doesn’t deny it. He takes her to the top of a mountain, out of the cloud bank, and shows her how a vampire’s skin sparkles in the sunlight. He explains how the Cullen family has learned to live on animal blood and consider themselves “vegetarian vampires.” Still, I am a killer, he says, and admits that he’s never wanted a human’s blood as much as he wants hers. I don’t care, Bella replies. Edward goes on to explain that Carlisle turned him in 1918 when he was dying of Spanish influenza and that Waylon was killed by some other vampires…not the Cullens. The relationship between Bella and Edward progresses to the point where Edward decides to take Bella home to meet his family. All of the Cullens are super-welcoming to Bella…except for Rosalie, who is concerned that the relationship between Edward and Bella may end badly (i.e., Edward will end up harming Bella), implicating the entire family and forcing them to move again. However, Edward is super careful not to lose control when he’s around Bella, and the relationship continues to grow.
One rainy afternoon, Edward takes Bella out to play baseball with his family. In the middle of the game, three figures come walking out of the mist. Fearfully, the Cullens regroup, hiding Bella behind him. The intruders are the rogue vampires who have been feasting on humans, including Waylon Forge. They introduce themselves as Laurent (Edi Gathegi), Victoria (Rachelle Lefevre), and James (Cam Gigandet) and ask whether they can join the Cullens for a game. Thinking quickly, Carlisle agrees, saying that some of the family were leaving, and Laurent and the others can take their places– a cue for Edward to get Bella safely away before she is detected. Everyone moves back into the field to take their places. But suddenly, the wind shifts so that James catches Bella’s scent and realizes that there is a human in their midst. “You brought a snack,” he sneers and heads toward Bella. Edward jumps between them. Laurent backs off and agrees to leave, taking James and Victoria with him. “Get Bella out of here,” Carlisle warns Edward. As they quickly drive away, Edward explains to Bella that James is a tracker. Now that he’s got her scent, he won’t give up until he has her. Bella’s only salvation is, if they can get to James first, rip him apart, and burn the pieces.
Edward’s plan is to catch a ferry to Vancouver, B.C.; but Bella insists on going home first, against Edward’s better judgement. They plan a ruse to get Bella quickly in and out of the house without her father knowing what’s happening. When Bella gets home, she runs into the house and slams the front door, shouting, “It’s over!” at Edward. She then informs her father that she’s got to get away from here…now! She packs a nightbag and, against her father’s protests, gets in the truck (where Edward is waiting), and they drive away. Unfortunately, James has already tracked Bella to Charlie’s house and is on their trail. First, they stop at the Cullens’ house, where Laurent has shown up to warn them about James and Victoria. The plan now is for Alice and Jasper to drive Bella south, while the others, including Rosalie and Esme dressed in Bella’s clothes, attempt to create a false trail through the woods. It doesn’t take long, however, for James to realize that he’s been duped.
When James changes his course, Alice senses the change and has a vision of James heading to a ballet studio in Phoenix where Bella once took lessons. While Jasper and Alice check them into a hotel in Phoenix, Bella gets a call on her cellphone from her mother, frantically worried about her. Suddenly, James comes on the line and informs Bella that he got her Phoenix address from Forks High School and arrived there just as her worried mother also got there. If Bella wants to save Renée’s life, she must ditch Jasper and Alice and meet James in her old ballet studio. Bella takes a taxi to the studio; but, when she gets there, she finds that it was a trick. James got an old movie from her house, and it was only Renée’s voice Bella was hearing. James then taunts her further by threatening to film their “time together” to break Edward’s heart.
As the camera rolls, James bats Bella around the room, then breaks her leg. Suddenly, Edward shows up, having gotten there faster than the others because of his greater speed. With their vampire strength, James and Edward toss each other around the room, breaking mirrors and windows with the impact of their bodies. At one point, James manages to swoop down in Bella and bite her arm. Just then, Carlisle, Alice, Emmett, and Jasper show up. Alice races to Bella’s side, while Carlisle pulls Edward off James, telling him that Bella needs him more. Overpowered by the smell of Bella’s blood, Alice asks Carlisle to take over for her. While Carlisle bends over Bella, Alice breaks James’ neck; and she, Jasper, and Emmett start a fire to burn his body. Carlisle says that Bella’s femoral artery is severed and she’s losing a lot of blood…but even more important is the fact that she’s been bitten, and the vampire venom has begun to affect her. Edward has a decision to make…either let the change happen or suck out the venom. Edward refuses to allow the change, so he decides to suck out the venom even though it means that he might not be able to stop.
When Bella awakens, she is in the hospital, her mother at her side and Edward asleep in a chair. Bella claims not to remember anything that happened, so Renée tells her how Edward and his father came down from Forks to persuade her to return; and, when Bella went to see them at their hotel, she tripped, fell down two flights of stairs, broke her leg, went through a window, and lost a lot of blood. When Renée leaves to get Charlie, who’s waiting in the hospital cafeteria, Edward “wakes up”. He tells Bella that they took care of James and that Victoria ran off. Then he lowers the boom. He wants Bella to move to Jacksonville with her mother so that she can’t be hurt anymore by her association with him. Bella refuses.
Bella moves back to Forks with her dad. With her leg still in a cast, Bella attends the prom with Edward. When Edward goes off to park the car, Jacob sits down next to Bella. He tells her that his father wants her to break up with Edward and that he sent a warning: “We’ll be watching you.” Bella laughs. Later, as Bella and Edward dance in the gazebo, she asks him why he didn’t let her turn. “If you just let the venom spread,” she says, “I could be like you by now.” She informs him that she’s made the decision to be with him forever and offers him her neck. Edward bends over to bite her neck but ends up simply kissing it. “Is it not enough just to have a long and happy life with me?” he asks. “For now,” Bella replies.
From a window overlooking the gazebo, Victoria watches Bella and Edward kiss. She turns away, lets down her hair, and smiles to herself.