The upcoming “Star Wars” standalone film, “Rogue One,” will follow a group trying to steal the Death Star plans, it was revealed at Sunday’s Star Wars Celebration, which also showed a special teaser for the upcoming spinoff.

“A band of resistance fighters unite for a daring mission to steal the Death Star plans in ‘Star Wars’ anthology film, Rogue One,” the official Star Wars account tweeted on Sunday.

Felicity Jones, who was previously confirmed to star in “Rogue One,” will play a rebel soldier. The film will take place between Episode III and Episode IV, but closer to “A New Hope.”

The news was revealed at a panel with Lucasfilm president Kathleen Kennedy, Lucasfilm SVP of development Kiri Hart and “Rogue One” director Gareth Edwards. Josh Trank was scheduled to appear at the panel to discuss his own standalone film, but wasn’t on hand, with moderator Pablo Hidalgo saying he was “under the weather.”

The “Rogue One” teaser opened with a somewhat idyllic bird’s-eye view of a lush forest planet, showing a TIE fighter soaring above the trees before the camera pulled back to reveal the Death Star in close orbit. The teaser utilized one of Alec Guinness’ lines from “A New Hope” in voiceover, as Obi-Wan Kenobi explained, “For over a thousand generations the Jedi Knights were the guardians of peace and justice in the Old Republic. Before the dark times. Before the Empire.”

The final moments of the teaser ended on a chilling note, as garbled distress messages from what sounded like soldiers or pilots crackled over a radio frequency, before the sound and title card fizzled out as if the signal had been abruptly cut off.

Since the film doesn’t begin shooting until this summer — where it will lense in the U.K. and other undisclosed locations around the world — the footage was wholly comprised of CGI wizardry from Industrial Light & Magic. Edwards also revealed a concept art image that showed a squad of soldiers on the muddy ground and in low-hovering crafts at night, faces covered and guns up as they ran towards an unseen threat in the rain.

(Image courtesy of StarWars.com)

Edwards emphasized that the film is first and foremost a war movie, “It’s called ‘Star Wars,'” he pointed out wryly. Below-the-line talent and production heads have previously worked on a number of combat films, with Edwards name-dropping “Zero Dark Thirty,” “Black Hawk Down” and “Saving Private Ryan” to give fans an idea of “Rogue One’s” inspirations.

Since “Rogue One” takes place in the aftermath of the destruction of the Jedi order, Edwards said, “The absence of the Jedi is omnipresent.” Instead of characters relying on the power of an unpredictable Force to save them, the film will center around “real,” grounded human issues. “It’s about the fact that God’s not coming to save us… we have to do this ourselves,” Edwards said. “It comes down to a group of individuals that don’t have magic powers… that have to bring hope to the galaxy.”

Edwards noted that what he loved about the original “Star Wars” trilogy was that it was a very “black and white” universe — with the lines between good guys and bad guys very clearly delineated. “Rogue One,” however, will focus on the shades of grey in the galaxy far, far away — the bad guys can be good and the good guys can be bad.

The film was described as an ensemble piece, despite Felicity Jones being the only announced cast member at this point. Edwards said he wasn’t interested in showing superhuman soldiers who are constantly strong and unfaltering throughout. “We wanted to see fear, humor, warmth,” he said, noting that Jones has embodied those qualities throughout her career.

Hart said the standalone movies are being called “anthology films” rather than spinoffs, and will delve into previously untapped corners of the established universe. “‘Star Wars,’ as much as it is a set of characters… is a a place that we can explore in terms of character, in terms of time frame… We really wanted freedom to do some films that would stand on their own — they can vary in scale, they can vary in genre, they can introduce new characters and new places, and they can still be ‘Star Wars.'”

Kennedy credited George Lucas with encouraging the idea for the anthology films. “It was really George’s idea, not only picking up the saga again — which he never envisioned he would do… he was really interested in exploring all the stories that might exist within the universe.”

The concept for “Rogue One” originated with John Knoll — visual effects supervisor and chief creative officer at Industrial Light & Magic — who pitched the idea to a number of colleagues at the company before taking it to Kennedy.

Kennedy admitted that she was worried about “opening the floodgates [for pitches] if I said yes,” but said that after hearing Knoll’s idea for “Rogue One,” she realized, “there is no way I’m going to say no, this is a really, really cool idea… ‘Star Wars’ stories are not a dime a dozen — this is really hard to do and really hard to get right.”

While fans know very little about the specifics of the mission to steal the Death Star plans from the Empire, Knoll noted that some parameters have been set by the previous movies. “You can’t just do anything — it has to logically fit into that framework,” which allowed him to “craft a good, solid, logical” story to explore this previously untold part of the “Star Wars” mythos.

Because the film is also taking place in the same timeframe as Disney XD’s “Star Wars Rebels” series, Hart hinted that there was possibility for crossover between the two properties. “We can look for ways for them to talk to each other, but we don’t mandate that… [executive producers] Dave Filoni and Simon Kinberg did an amazing job on ‘Rebels,’ and we are facilitating the development of ‘Rogue One’ as well, so we’ll be seeing what happens there. We’re very much aware that things are happening on the same part of the timeline,” she said.

Perhaps because Trank wasn’t present, no information was released about the upcoming standalone film that he was previously announced to direct.

“Star Wars: Rogue One” is scheduled to be released in December 2016, while the J.J. Abrams-directed “Star Wars: The Force Awakens” will hit theaters on December 18, 2015.