Wyck Godfrey and Karen Rosenfelt served as executive producers for the film, along with the author of the series, Stephenie Meyer; the screenplay was written by Melissa Rosenberg, the screenwriter of the first three entries. It was released in theatres on November 18, 2011, and released to DVD on February 11, 2012 in the United States. The film grossed over $712 million worldwide.
Bella Swan plans her wedding to Edward Cullen, with which she will become part of the Cullen family. Before the wedding, Edward tells Bella that he has murdered people in the past. Undaunted by this, Bella marries him nonetheless, and during the reception that follows, she is visited by her friend, Jacob Black. While dancing with Jacob, Bella admits that she and Edward plan to consummate their marriage during their honeymoon. Jacob becomes furious, knowing how dangerous it will be for Bella and that Edward could easily kill her, but he is quickly restrained by his pack. He then runs off into the woods, and Edward takes an upset Bella back to the reception.
The couple spends their honeymoon on Isle Esme, the Cullens' private Brazilian island that Carlisle had given to Esme as a gift. Although hesitant, Edward has sex with Bella for the first time. The next morning, Edward realizes that he bruised Bella's arms, back and shoulders during sex and is furious with himself for hurting her, vowing to never be intimate with her again, much to her disappointment. She tries tirelessly to seduce him , and he finally gives in to her. Two weeks into their honeymoon, Bella discovers that she is pregnant. Despite the fact that she has only been pregnant for a few days, she is experiencing symptoms and has a defined bump, as the baby is growing at an extraordinarily accelerated rate. After consulting with Carlisle, they rush back to Forks. When Bella realizes that Edward intends to kill her baby, she is horrified, wanting to keep Edward's child, already having grown attached to it. She enlists the help of Edward's sister, Rosalie, who has always wanted a child, to help protect her baby.
When Jacob hears that Edward and Bella have returned home, he rushes over to the Cullen's on his motor bike, expecting Bella to either be dead or a vampire. Instead, he finds her already heavily pregnant, and frail due to her vampire-human child. Jacob tells the pack and, opposed to Sam Uley's plans to kill Bella and her child, which is thought to be a demon, Jacob angrily leaves his pack and arrives at the Cullens' to protect Bella. His tribemates, Seth and Leah Clearwater, join him, forming a new wolf pack with Jacob as the Alpha. As the pregnancy progresses, Bella's health severely deteriorates. As a last resort, she begins drinking human blood, which satisfies the fetus' vampiric thirst and allows her to regain some strength. Soon afterward, Bella goes into a painful labor and gives birth to her daughter, Renesmee, aportmanteau of the names of Bella's mother, Renée and Edward's adoptive mother, Esme. To save her life, Edward injects Bella's heart with his venom to transform her into a vampire, but nothing seems to happen and Bella is thought to be dead. Greatly distraught, Jacob attempts to kill the baby, but stops when he realizes he has imprinted on the child.
When the werewolves learn of Bella's death, they attack the Cullens' house in an attempt to kill the baby. They are forced to stop after learning Jacob has imprinted on Renesmee (the involuntary response by which a werewolf finds his soul mate), which means that under their wolf law, Renesmee cannot be harmed. After Bella is thought to be deceased, Carlisle notices there's a slight pulse and tells Edward and the rest of the Cullens as they clean the body. After Bella's body is cleaned and dressed, her wounds from her difficult labor heal as the venom spreads through her body. Bella's heart finally ceases, and she awakens as a newborn vampire.
In a post-credits scene, the Volturi hear about Bella's conversion; Aro notes that it does not end their dispute with the Cullens, proclaiming, "They have something I want".
