Under the stewardship of director David Slade, teen heartthrobs Rob Pattinson and Taylor Lautner (playing vampire Edward Cullen and werewolf Jacob Black) vie for the affections of Kristen Stewart (the all-too-human Bella Swan) amidst the growing tensions between camps of vampires, werewolves and the emerging army of newborn vamps under the dominion of Bryce Dallas Howard (playing the deadly Victoria). Edward and Bella - the star-crossed lovers of all the Twilight movies - are planning to get married so that she may finally make the transformation from human to vampire and thus make their love immortal. At issue is the love triangle forming when Bella realizes she also has feelings for werewolf Jacob though she's sworn herself to Edward.

As passions erupt between the three protagonists, Victoria's newborn vamp army grows in strength and menaces the community which forces an alliance between the Cullens and the Wolf Pack. Retreating to the woods, the newly allied vampires and werewolves begin to train to defend against the newborn army. Edward and Jacob join forces in the mountains to protect Bella from harm and though Bella lowers her guard and kisses her werewolf admirer, she must ultimately surrender to her vampire true love Edward.

In the epic battle against the newborns, the vampires and the wolves defeat Victoria and her minions and Bella declares to Dakota Fanning (Jane) her plans to marry Edward and become vampire. Eclipse draws to a close as Edward and Bella return to the meadow to share their feelings and move forward with their eternal bond.