With only six months to go before we see how Rebel spies infiltrated the Empire and stole the plans for the original Death Star in Rogue One: A Star Wars Story, a new behind-the-scenes reel premiered at London’s Star Wars Celebration Friday, shortly before a new trailer boasting the biggest tease of all: the return of Darth Vader.

The three-minute BTS clip, while not heavy on plot details, features a trove of striking new shots from the upcoming war epic: explosions on the tropical beaches of Scarif, a Death Star-adjacent planet; a column of flames billowing up behind Donnie Yen’s blind warrior Chirrut Imwe; Stormtroopers rolling through a Mos Eisley-like city in a tank; Ben Mendelsohn’s villainous Orson Krennic flanked by Death Troopers and Imperial officers.

And, excitingly, we then catch a brief, slow-mo glimpse of a chaotic battle featuring Diego Luna’s Captain Cassian Andor and Felicity Jones’s Jyn Erso—the latter clutching what looks like a hard drive, possibly containing the coveted plans for the Death Star.

In voiceover interview snippets, director Gareth Edwards (Godzilla) and a handful of cast members emphasize two of the film’s strongest selling points: its limited use of green screens (Star Wars still isn't done apologizing for the sins of the CGI-fueled prequels) and of course, nostalgia.

Jones, who is seen running from an explosion in a street littered with dead Stormtroopers, muses on the impact of using practical effects: “Your heart’s beating and you’re actually in this situation,” she says. “You get something very genuine that you couldn’t have planned.” (Comically, her last words coincide with a piece of debris falling on her head.)

Edwards describes the heightened pressures of making this sort-of prequel to A New Hope and the challenge in paying respects to the original trilogy while still crafting a new, separate identity. “We’re making a film touching my favorite movie of all time,” he says. “But then if you’re too respectful of it, that you daren’t do anything new or different [or] take a risk, then what are you bringing to the table?”

The task is daunting and Edwards does sound nervous, but his childlike enthusiasm about the whole thing (just watch him mimic an X-wing's flight trajectory while directing actors on the beach) still shines through: “That kid, when you were four years old, playing with Star Wars figures—it’s a lot like being that kid again,” he says.

But it’s the last line in the trailer that cashes in on the nostalgia. Jyn—who had the last teaser trailer’s most talked-about line: “This is a rebellion, isn’t it? I rebel”—faces her comrades in the cargo hold of an airship. With a wry smile she says, “May the Force be with us.”

Her team is going to need it. Actor Jiang Wen, who plays mercenary Baze Malbus, accidentally revealed that a major character dies in the film during its livestreamed hype panel in London, where cast and crew sat alongside Edwards and Lucasfilm boss Kathleen Kennedy. (Possible spoiler ahead, obviously.) When describing his character Baze's relationship with Yen's Chirrut, Wen said of his friend, "He and me was a partner—he of course believe in Force but my character doesn't believe in Force. But I pretend all of them—not them, just them [gesturing toward cast members]—to do very, very big mission."

Then, before anyone could stop him, he went on: "And when this guy dead, I do something better. Maybe I believe by my action. He's thinker and doer." There's room for misinterpretation—maybe he misspoke. But from the alarmed look on Yen's face, the exasperation on Edwards's, and moderator Gwendoline Christie's panicked interjection ("I think you've gotta leave it there!"), that was clearly something we weren't meant to know.

It was a charming if accidentally disastrous beat during an otherwise by-the-numbers Rogue One panel (Wen, of course, isn't the first cast member to blurt out too much—Mads Mikkelson already gave away his role as Jyn Erso's father). But the most exciting moment came with yet another new trailer which, sorry everyone, has yet to be uploaded to YouTube.

The new footage begins with a little girl, likely a young Jyn Erso, running across a rugged field resembling the one where we've seen a Death Trooper holding a miniature toy Stormtrooper, the one said to have "special significance" in the movie. A grown-up Jyn then portends the importance of the battles ahead: "Every day we grow weaker, while they grow stronger. This is our chance to make a real difference."

Then, the deadly tantalizing final shot: a glistening black floor, a reflection, and the silhouette of a frightening, familiar figure, drawing a rasping mechanical breath. Darth Vader, at the height of his powers, just made his Rogue One debut.

James Earl Jones will be reprising his voice role as the Sith lord formerly known as Anakin Skywalker, though Kennedy has said he will be used in the movie only "sparingly." That's for the best—while it'll be exciting to see one of the most powerful Force-wielders in the galaxy in his prime, Edwards has stressed that the prequel is trying to set itself apart from more traditional Star Wars stories in tone and story. Part of that will come from letting Mendehlson's Director Krennic (and that sweet, sweet space cape) take center stage as the villain. How the rest of the film turns out will be revealed on Dec. 16.