The book begins with reports of attacks occurring in Seattle. Alice has a vision where she sees Victoria attempting to hunt Bella in retaliation of the death of her lover James by the hands of the Cullens. Edward believes that the attacks are in correlation with newly formed vampires, or newborns, that cannot control their hunger.
Bella wants to make amends with her friend Jacob, and visits him in La Push when Edward is away investigating the murders. Jacob is still wholly in love with Bella and believes they are meant to be. When he attempts to kiss Bella, she ends up punching him, but due to his werewolf strength, she ends up breaking her hand.
When Jacob learns of the threat against Bella, he persuades the wolves to join the Cullens in their fight against the newborn vampire army. Bella is taken to the mountain as a safe spot when the battle occurs. She uses Jacob’s body heat to keep warm, and Edward becomes jealous as a result.
When Bella wakes, she speaks to Edward about their engagement, which Jacob overhears and leaves in anger and hurt. Jacob threatens to kill himself in the battle because he believes he cannot live without her love. Bella kisses him and realizes that she too is in love with him. However, she still loves Edward more.
Meanwhile, Victoria soon finds Bella’s location and attempts to kill her, but Edward intervenes and kills her. The Volturi then arrive to kill Victoria’s army, but they also note that Bella has still not been changed into a vampire even though the Cullens pledged she would be. The Cullens confirm that her date for changing has been set, and the Volturi leave.
After the battle, Bella visits Jacob, who finally realizes that Bella really does love Edward more. Bella and Edward then go to their meadow where they agree to get married before having sex and changing her into a vampire. In the epilogue, Jacob receives the wedding invitation and runs away, phasing into his werewolf due to the pain he is experiencing.