Lord Voldemort is tightening his grip on both the wizarding and Muggle worlds and has chosen Draco Malfoy to carry out a secret mission. Severus Snape makes an Unbreakable Vow with Draco's mother, Narcissa, to protect Draco and fulfill the assignment if he fails.
Bella awakens from her transformation from human to vampire, aware of her new abilities, but unaware of changes within the coven, such as Jacob having imprinted on her child, Renesmee. It also appears that Bella's father, Charlie, has been attempting to contact the Cullens for updates on Bella's illness. They intend to tell him she didn't survive, which requires that they move out of Forks, Washington to protect their identities. Jacob, desperate not to lose Renesmee, tells Charlie that his daughter is in fact alive and well, and explains that Bella has had to change in order to survive. He morphs into a wolf, revealing his tribe's shape-shifting power, but does not tell Charlie about vampires.
Harry Potter, now aged 13, has been spending another dissatisfying summer at Privet Drive. When Uncle Vernon's sister, Marge, insults Harry's parents, he becomes angry and accidentally causes her to inflate and float away. Harry flees with his luggage, fed up with his life with the Dursleys. The Knight Bus delivers Harry to the Leaky Cauldron, where he is forgiven by Minister of Magic Cornelius Fudge for using magic outside of Hogwarts. After reuniting with his best friends Ron and Hermione, Harry learns that Sirius Black, a convicted supporter of the dark wizard Voldemort, who murdered Harry's parents, has escaped Azkaban prison, intending to kill Harry.
Bella Swan is getting ready for her wedding. During the reception, her best friend, Jacob Black the were-wolf returns after hearing about Bella and Edward's engagement. While dancing with him in the woods, away from everyone else, Bella admits that she and Edward plan to consummate their marriage on their honeymoon while she's still human. Jacob becomes furious, knowing that Edward could easily kill Bella but the other wolves restrain him from hurting Edward.
On her 18th birthday, Bella Swan wakes up from a dream in which she sees herself as an old woman. She expresses her distaste about growing older than her boyfriend Edward Cullen, a vampire who stopped aging physically at 17. Despite her lack of enthusiasm, Edward's adoptive family throw Bella a birthday party. While unwrapping a gift, Bella gets a paper cut. Edward's brother, Jasper, becomes overwhelmed by the scent of Bella's blood and attempts to kill her. Realizing the danger that he and his family pose to Bella, Edward ends their relationship, and the Cullens leave Forks, Washington.
In Seattle, not far from Forks, Victoria (Bryce Dallas Howard) attacks and bites Riley Biers (Xavier Samuel), in order to begin creating an army of newborns with him. Back in Forks, Edward Cullen (Robert Pattinson) and Bella Swan (Kristen Stewart) discuss the complications of becoming an immortal vampire. At 18 years old, one year older than the age Edward was when he became a vampire, Bella expresses her aversion to the idea of marrying so young, though Edward refuses to turn her into a vampire until they are married, his argument that she should have various human experiences she would otherwise miss. While Charlie Swan (Billy Burke) investigates the disappearance of Riley Biers, Edward suspects his disappearance was caused by the newborn vampires, furthering his suspicions is Riley's intrusion into Bella's room.
A short time after the first film, Mavis (Selena Gomez) and her fiance Johnny (Andy Samberg) are married, with the approval of her father Dracula (Adam Sandler) and the world has become aware of (and unfased by) the existence of monsters. Mavis later reveals to Drac that she is pregnant and a year later, she gives birth to a son named Dennis (Asher Blinkoff), who befriends Wayne's werewolf pup daughter Winnie (Sadie Sandler). Nearing his fifth birthday, Dennis has yet to grow his fangs and Drac worries that his grandson might not gain vampire powers. Noticing the dangers of Transylvania, Mavis starts to consider raising Dennis where Johnny grew up, much to Drac's disapproval.
Seventeen-year-old Isabella "Bella" Swan moves to Forks, a small town on the Washington coast, to live with her father, Charlie. Her mother, Renée, is remarried to a minor league baseball player, and they are often traveling. Bella makes many friends at her new high school, but she is intrigued by the mysterious and aloof Cullen siblings. Bella sits next to Edward Cullen in biology class on her first day of school, but he seems to be repulsed by her. A few days later, Bella is nearly struck by a van in the school parking lot. Edward saves her by instantaneously covering a distance of some 30 feet and putting himself between Bella and the van, stopping it without injury with only his hand. He subsequently refuses to explain his actions to Bella and warns her against befriending him.
In the aftermath of the death of Dracula's wife Martha (Jackie Sandler) at the hands of an angry mob, Count Dracula (Adam Sandler) designs and builds a massive five-star hotel in Transylvania in which to raise his daughter Mavis (Selena Gomez) and to serve as a getaway for all the world's monsters.
In 1887, Transylvanian Doctor Victor Frankenstein brings to life his Monster with the aid of his assistant Igor and Count Dracula. After Dracula betrays and kills Doctor Frankenstein, the Monster escapes to a windmill, which is burned down by a pursuing mob. The mob flees as Dracula and his three brides mourn the loss of the Monster.
Six months after the events of the second film, humans have captured Selene during "The Purge", a global military crusade to exterminate vampires and lycans. Vampires have waged guerrilla warfare against the government, but the humans have overrun them, forcing the survivors to hide underground and resist the humans on their own.
Zach Cooper (Dylan Minnette) and his mother Gale (Amy Ryan) move from New York to the fictional town of Madison, Delaware. Their new neighbors are the mysterious "Mr. Shivers" (Jack Black) and his daughter Hannah (Odeya Rush), but when Zach tries to introduce himself, Mr. Shivers warns him to stay away from them. At school, Zach befriends Champ (Ryan Lee), an often bullied, socially awkward student. One night, Zach hears Mr. Shivers and Hannah arguing from his window, followed by Hannah screaming. He calls the police, but Mr. Shivers assures the officers that nothing is wrong and the scream was from a movie. Fearing Hannah is in danger, Zach tricks Mr. Shivers into going to the police station for further questioning.
Will Randall is bitten by a wolf while driving home in Vermont. Afterwards, he is demoted from editor-in-chief of a publishing house when it is taken over by tycoon Raymond Alden, who replaces him with Will's protégé Stewart Swinton. When Will thinks that his wife Charlotte is having an affair with Stewart, he rushes over to his house where Stewart sees Will angry and asks him what the problem is. Will bites Stewart and rushes upstairs to the room to find Charlotte half-naked. His worst fears are confirmed. Will becomes more aggressive, taking on the characteristics of a wolf.