After the birth of Renesmee/Nessie, the Cullens gather other vampire clans in order to protect the child from a false allegation that puts the family in front of the Volturi.
Bella (Kristen Steward) awakens from her transformation into a vampire (from BD Part 1) and reunites with Edward (Robert Pattinson) and their child Renesmee. Renesmee, being a human/vampire hybrid, grows very quickly which concerns the Cullen clan as no other child like her is known to exist. While Bella, Renesmee and Jacob (Taylor Lautner), who imprrinted on Renesme in BD Part 2, are walking one day, Irina, a vampire who loved Edward and is jealous of Bella, sees the three and assumes that Renesmee is an immortal child – a child who is turned into a vampire during its formative years. The Volturri stricts forbids the production of immortal children and the punishment is death to the child and its creators. The Volturri decide to attack the Cullens but Alice sees them coming and in order to defend themselves, they attempt to gather as many witnesses among their friends to prove that Renesmee isn’t an immortal child.
The day of the battle arrives. The Cullens, the wolves and about a dozen of the vampire witnesses stand against Aro (Michael Sheen) and the Volturri soldiers. Renesmee “shows” Aro that she is not an immortal child through her special power of communication and Aro concedes. He has Irina killed for bearing false witness. Alice and Jasper reappear after having fled weeks earlier in order to avoid capture from the Volturri and she shows Aro a glimpse of the future if the Volturri decide to attack anyway – it would lead to the total destruction of Aro and all of his men. Alice also presents them with another haf human/half vampire named Nahuel whom she found in Brazil – a man who bears no threat to mankind for his unique “halfness”. The Volturri decide to leave in peace and the Cullens bid farewell to their vampire friends.
Weeks later, Bella and Edward have settled into their peaceful life. Renesmee continues to grow and we learned that Nahuel was about 150 years old but had reached full maturity seven years after his birth. So Renesmee can expect to have a long life with Jacob at her side.
In the end, Bella taps into her power as a “shield” to show Edward her thoughts, a montage of their first meeting up to their marriage. Bella says no one has have loved someone more that she loves Edward and Edwards asks to read her thoughts again.
This movie picks up where the last one left off, with Bella (Kristen Stewart) waking up as a newly transformed vampire. She immediately notices the differences in her senses – noticing dust particles in the air and the textures/details of items in the room. She finally focuses on Edward (Robert Pattinson) and embraces him, though Edward is clearly uncomfortable and explains that Bella is now stronger than him since she’s a newborn vampire. Bella asks to see their newborn daughter, Renesmee, but Edward explains that she must deal with her thirst for blood first.
Edward and Bella go to the woods on a hunt, and Bella ends up smelling a human in the distance and nearly attacks him. However, she gets control of herself in time and runs away, taking down a mountain lion instead. Edward explains that it’s rare to have such control for even older vampires, let alone a newborn. Nevertheless, they decide on one more test before seeing Renesmee, and that’s by testing her control with Jacob (Taylor Lautner). But in fact, Bella just jokes about how much Jacob smells like a dog.
With the tests out of the way, Bella finally meets Renesmee, who looks at least a few months old. Carlisle (Peter Facinelli) explains that the baby is growing at an unprecedented rate, and they have no idea what to expect with her aging. Bella also finds that Renesmee (who’s half human, half vampire) has a gift like some of the other vampires – when touching one’s cheek, she can share her thoughts with that person – and shows Bella that she recognizes her as her mother.
During this meeting, Bella notices that Jacob is very protective of Renesmee, which makes her suspicious. She finally gets Jacob to admit that he has imprinted on Renesmee (the wolf equivalent of soulmates), which upsets Bella greatly. She starts pushing Jacob around angrily, but backs off when she almost hurts Seth accidentally. Back in the house, Alice (Ashley Greene) presents Bella with a gift – a key to a nearby house that has been built for Edward, Bella, and Renesmee.
The next morning, the Cullens start to plan where they will move to, since they will have to fake Bella’s death. Jacob becomes concerned about losing Renesmee, so he goes to see Bella’s father, Charlie (Billy Burke), and shifts into a wolf in front of him. Jacob convinces Charlie that things are “different,” but that he should go see Bella. And although he notices that Bella looks and seems different, he agrees not to ask questions in exchange for having Bella in his life (so the Cullens won’t have to move after all). After Charlie leaves, Jasper (Jackson Rathbone) compliments Bella on her restraint despite being a newborn, and Emmett (Kellan Lutz) laughs that she’s no newborn. This leads to an arm wrestling match where Bella beats Emmett easily, and everyone is light-hearted.
All seems right with the Cullens, and it’s presumed that at least a few months pass, as Renesmee now looks like a six or seven year-old. Bella is now in the woods with Jacob as they watch Renesmee play, and they see a figure off in the distance. Bella recognizes that it is Irina (Maggie Grace), one of the Cullens’ “cousins” from Denali. But Irina looks visibly upset when she sees Renesmee, and runs off before Bella can speak with her.
Cut to Italy, where Irina has now gone to see the Volturi. She says that she has come to report a crime committed by the Cullens, that they have created an immortal child. Back in Forks, Alice sees this vision, and realizes that the Volturi will be coming to Forks to kill them all.
Carlisle explains that many years ago, vampires (including Irina’s mother) used to change children into vampires. However, these children could not mature and were frozen at their age, so they were impossible to control and risked exposing vampires to the humans. Therefore, the Volturi destroyed all the immortal children and their creators, and it has been forbidden ever since. Bella argues that Renesmee isn’t an immortal child and grows every day, but the Cullens explain that it doesn’t matter; the Volturi have been looking for an excuse to get rid of the Cullens for some time since they’ve become so strong. Aro (Michael Sheen, the head of the Volturi) also wants to capture Alice, since her ability to see the future is a gift he wants to collect for his army.
The Cullens decide that they need to gather enough vampires to witness Renesmee’s growth that the Volturi will have to take pause and listen to reason. However, as they pack up their things, they realize that Alice and Jasper have gone missing, leaving a note on a page ripped out of a book that simply says to continue looking for witnesses.
We then see cutscenes of the Cullens gathering about twenty witnesses, many of whom are old friends of Carlisle’s. One of these witnesses, Eleazar (Christian Camargo), is able to determine vampires’ gifts, and informs Bella that she is a shield against other vampires’ gifts (which is why Edward could never read her thoughts, or the Volturi could not attack her with their powers in earlier movies). Bella tries to train this gift so she can expand the shield to protect others, but can only do so on a small scale and for short amounts of time.
A few days before the Volturi are scheduled to arrive, Bella looks at Alice’s note again, noting that the page she ripped out is the title page of The Merchant of Venice. She notices the book on the shelf, and finds a hidden note from Alice that says something like “J. Jenks, Seattle – Burn this.” Bella realizes that Alice wanted Bella to find this message since her thoughts would be protected from Aro. She burns the book, but travels to Seattle a few days later to meet with Mr. Jenks (Wendell Pierce). It turns out that Jenks forges documents, and provides her passports and documentation for Renesmee and Jacob only. This clearly devastates Bella, as it implies that she and Edward will not survive the Volturi encounter. Nevertheless, she secretly packs this in a bag for Renesmee to hold onto during the confrontation.
Finally, it is time for the Volturi to arrive, and the Cullens and their witnesses are met by the Volturi in a large, snow-covered field. Though the wolf packs also show up to help the Cullens, they are clearly outnumbered by the Volturi by at least 3:1. Carlisle comes forward to talk to Aro, and explains that Renesmee is not an immortal child and no rules have been broken. Aro asks to meet Renesmee, and agrees that she isn’t an immortal child after all. The Volturi immediately kill Irina for her false claim, but then Aro begins to argue that there’s no way to prove Renesmee won’t become a danger to exposing vampires in the future, so he’s leaning toward killing her anyway. However, as things start to become heated, two figures emerge from the nearby woods: Alice and Jasper. They have returned from South America where Alice claims she can prove that Renesmee will cause no danger. Aro takes Alice’s hand to read her thoughts, but Alice looks disgusted, realizing that he won’t change his mind no matter how much proof they have.
Alice turns to Bella and whispers “Go now,” to which Bella sends Jacob and Renesmee running from the field. Aro has his guards take hold of Alice and Jasper, which angers the Cullens greatly. Carlisle steps forward to attack, and he and Aro meet each other midair. We then see Aro land on the ground, Carlisle’s decapitated head in hand. He burns Carlisle’s body, which causes the Cullens and their witnesses to launch into a large attack. Deaths are occurring on both sides, with the Cullens losing at first. We see Jasper get killed by the Volturi, and Seth killed while in wolf-form. One of the vampires uses his gift to create a chasm in the earth, which kills many of the Volturi but almost kills Edward as well. However, he is able to grab onto the rock wall, climb out, and rejoin the battle.
During this time, it’s clear Bella has learned to better control her power, and is able to protect her friends and family long enough to gain the upper hand. We see Jane (Dakota Fanning) and Alec (Cameron Bright) from the Volturi killed, followed by Marcus (Christopher Heyerdahl) and Caius (Jamie Campbell Bower). Finally, we see Edward and Bella attacking Aro, and ripping his head off.
Suddenly, we’re transported back into the peaceful field, and it’s clear that the whole battle was a vision that Alice was showing to Aro. Alice warns him that he should change his decision, or else it won’t end well for him. Alice is able to prove that Renesmee will reach maturity after seven years of growth, and will not pose a threat to exposing vampires. She introduces one man who is 150 years old and also half-human, half-vampire, and Aro is forced to concede. Not wanting to lose the battle, he and the Volturi retreat, with the Cullens celebrating their victory.
The Cullens return to their home and are happy to celebrate. Alice ends up seeing a vision of Renesmee grown up, with her and Jacob happy together. We also see Edward and Bella in her future vision, showing that they will get to see their daughter grow up after all. Finally, we end with Edward and Bella back in their meadow, where Bella has learned to lift her shield and show Edward her thoughts. She shows memories from their time together, proving how much she loves him. He says he feels the same, and that they now have forever to spend together.
As the credits begin, they do a nice series of credits showing all the major characters from all five movies.