Bella moves to a town called Forks, Washington to spend time with her father. There, she sees a group of teenagers who her friend Jessica tells her are the Cullens and Hales, adopted teenagers of Carlisle and Esme Cullen. They are all very beautiful and handsome, but act strange. Bella sits next to one of them, Edward, during her biology class, and he treats her meanly, sitting as far away from her as possible and later trying to switch classes so he wouldn't have to sit next to her. Later, her friend Jacob tells her some legends that the Cullens are vampires. Bella notices some strange things about Edward, such as super strength (lifting a van), ice-cold skin, and super speed. One night, she is with her friends in Port Angeles when she is cornered by some thugs in an alley. Edward saves her and takes her out to dinner, and on the way home, she asks him about being a vampire. She discovers it is true, but says that it 'doesn't matter' because she loves him anyway. The reason Edward was so mean to her was that the scent of her blood was so appealing to him, and he was trying not to attack her. Later, when a vampire named James is tracking Bella, Edward comes to save her when James tricks Bella into coming to a ballet studio where he is waiting for her. James bites Bella, but Edward manages to suck the venom out while his siblings kill James. At the end, Edward takes Bella to prom.
Bella becomes upset because it is her eighteenth birthday and she is physically older than Edward (who is 17, yet technically 118). Later, Bella notices that Edward is acting strange, and one day he tells her that he has to leave her, for her own good. Bella sinks into a state of depression where she doesn't talk to any of her friends or do anything but sit all day. She has horrible nightmares and wakes up screaming at night. During this time, she finds that Jacob can make her feel better, and she spends time with him. But she finds that if she is about to do something reckless or dangerous, Edward's voice will speak to her, begging her not to. So she cliff-dives to hear his voice and almost dies. Alice, Edward's sister, has the power of seeing the future, and sees Bellal jumping off of a cliff. Thinking that she was committing suicide, she boards a plane for Forks. Edward finds out that she did this and calls her house. Jacob answers the phone and Edward asks where Charlie, Bella's father, is, and Jacob responds, "At the funeral", because Charlie was at a funeral for a friend of his who died. Edward thinks that Charlie is going to Bella's funeral, and goes to Italy, where he can ask the Volturi (the vampire elders) to kill him too. Bella goes to Italy with Alice to stop him, and they all go back to Forks. Edward reveals that he was tracking Victoria, James's wife, who was hunting Bella. But he says he won't leave her again.
Bella tells Edward that before he turns her into a vampire, she wants to have sex with him. He agrees, but only under one condition: she marries him first. Bella is worried by the prospect of marriage, but agrees later. Victoria leads an army of newborn vampires to kill Bella, and Edward fights for her with his siblings and the werewolves.
Edward and Bella marry and have a honeymoon on Isle Esme, an island that belongs to Edward's mother. There, they have sex, but as Edward is a vampire and Bella is not, he accidentally bruises her all over. She doesn't mind, but he refuses to have sex with her again because he doesn't want to hurt her. Bella tries to make him, but he won't. Finally, one night, she wakes up crying because she had a dream about them having sex and wanted it to be real. Edward finally agrees. But later, Bella finds out that she is pregnant with a rapidly-growing half vampire-half human baby, and Edward is furious because there are stories of such babies killing the woman carrying them. Edward believes that they should abort the baby, but Bella already loves it and refuses. They find out that the baby needs blood, and Bella drinks some, which helps her for a bit. But when she goes into labor, she has to have an emergency C-Section, which kills her. Edward bites her everywhere so that she can become a vampire, but when she doesn't, Edward becomes distraught. Suddenly, she awakens as a healthy vampire. During the battle with the Volturi, Edward and Bella fight together. Then, they live together with their daughter Renesmee.
Edward and Bella have one daughter named Renesmee Carlie Cullen; her name is a portmanteau of Renee, Bella's mother, and Esme, Edward's mother. Jacob Black imprinted on Renesmee, meaning that he found his soulmate in her. As she is half-vampire/half-human, her physical age is much older than her chronological age. At the end of Breaking Dawn, she is three months old but has the physical age of around 3-4 years. Her mental age advances even faster than her physical age.
Ships between Edward & Bella and Jacob & Bella are the two most popular ships in the fandom, and fans take the sides of 'Team Edward', 'Team Bella', and 'Team Neutral'.