Brian Truitt

USA TODAY

Darth Vader is returning to give the Rebel Alliance trouble once more in Rogue One: A Star Wars Story, but in addition to bringing back an old favorite, director Gareth Edwards is introducing completely new landscapes to the galaxy far, far away.

Edwards, his cast and producer/Lucasfilm president Kathleen Kennedy discussed the upcoming stand-alone film (in theaters Dec. 16) and its characters at a panel Friday at London's Star Wars Celebration event. In addition, they presented the crowd with a behind-the-scenes sizzle reel for showcasing a handheld filmmaking style that Kennedy said is "an incredible way to immerse us in the movie.”

Set just before the events of the original 1977 Star Wars film, Rogue One follows a band of Rebel Alliance spies whose mission is to steal the plans for the Empire’s Death Star, a lethal weapon of mass planetary destruction — the same one that Mark Hamill’s Luke Skywalker helps take down in George Lucas’ original trilogy.

Rogue One will have story elements that will feel connective and similar to fans as well as being a blend of old and new, said Kiri Hart, the development lead of Lucasfilm’s Star Wars Story Group. “It’s grounded in this piece of Star Wars history that everyone knows happened.”

Played by Felicity Jones, the main heroine Jyn Erso is a ne’er-do-well enlisted to help in the secret mission, and unlike Luke or Daisy Ridley’s The Force Awakens heroine Rey, “Jyn is not a character who’s asking, ‘Where am I and where do I come from?’ ” Jones said. “We know where she comes from and that fact is what propels the story.”

Instead, the actress added, Jyn’s journey is to “find her reason and her cause.”

The panel's host, Force Awakens star Gwendoline Christie, presented Jones with her own action figure. “I feel very privileged to have joined the Star Wars doll universe,” she added.

Also in Jyn's squad is Rebel officer Cassian Andor, played by Diego Luna,who the actor says “has to keep them together. … Like any team there is friction and distrust.” His best friend is the new droid K-2SO, played via motion-capture by Alan Tudyk. “He speaks his mind and can say things that are unsettling,” Tudyk said. “He’s honest. If you know any old people, it’s just like that.”

And Riz Ahmed’s Bodhi Rook is an Imperial pilot whose home is one of the Empire’s occupied planets. “Stuff makes him question his career counselor,” Ahmed said. “People work at big organizations and they don’t agree with everything they do.”

Rogue One takes fans to quite a few different locales they've never seen before on screen. Jedha is a place where people still believe in the Force and have a spiritual connection with it even after the Jedi have been wiped out. (It’s also the home of two of Jyn’s teammates: Donnie Yen’s blind warrior Chirrut Imwe and Jiang Wen’s assassin Baze Malbus.) Plus, Edwards went to Maldives to film scenes set on the paradise planet Scarif and recruited Maldives soldiers to put on Stormtrooper armor for his film.

Ben Mendelsohn showed up to the Celebration panel dressed in regal gear as his villain Director Krennic, a man who’s “smarter than most of his predecessors,” said the Australian actor. Edwards also teased bad guy Darth Vader’s role in Rogue One, adding that he and sound editor Matthew Wood worked with James Earl Jones in December to bring back that iconic Imperial voice from the original Star Wars movies.

“He did this one line where he says the word ‘power,’ and we looked at each other and had this nerdgasm,” Edwards said. “We were reduced to 3-year-olds."