Distraught over Edward's leaving in New Moon, Bella finds friendship with Jacob and slowly emerges from her months-long depression. Their friendship grows strong, but Jacob also develops romantic feelings for Bella that she does not reciprocate. Jacob, a member of the Quileute tribe, is descended from an ancient line of "shape-shifters" that assume wolf form. The Quileutes are vampires' mortal enemies, and Jacob undergoes his first transformation into a wolf in response to a new vampire threat. He becomes busy patrolling the forest with his pack, searching for vampires in the area. When Bella is caught by the vampire Laurent alone in a clearing, she is saved by Jacob and the wolf pack, who chase and kill Laurent.
Bella, who has been taking dangerous risks to feel closer to Edward, impulsively jumps off a cliff and almost drowns, but Jacob saves her life. After Edward mistakenly believes she has died, Bella and Edward's sister, Alice Cullen, rush to Italy to stop Edward from killing himself, leaving Jacob hurt and angry. Jacob is disgusted by Edward's return and by Bella's willingness to take him back after he left her. Jacob reminds Edward of his tribe's treaty with the Cullen family, which states that the Cullens are not allowed to bite humans.