"Avatar: Fire and Ash" trailer reveals new Na'vi clan and villain, set for December 19 release.

The official trailer for "Avatar: Fire and Ash," the third film in James Cameron's Avatar franchise, has been released. The movie, set to debut on December 19, features Sam Worthington and Zoe Saldana as Jake Sully and Neytiri. The trailer introduces the Mangkwan clan, a new Na'vi group with fire-controlling abilities, and the villain Varang, played by Oona Chaplin. The film continues the story of Jake and Neytiri's family on Pandora.