(CNN) -- Metallica appeared at Comic-Con in San Diego on Friday to promote their upcoming 3-D IMAX concert film "Metallica Through the Never." The band debuted footage from the movie to a crowd of fans in the Convention Center's Hall H and later rocked an intimate crowd at a secret show.
"Metallica Through the Never" was directed by Nimrod Antal ("Predators") and intersperses live Metallica concert footage with a fictional narrative about a young roadie named Trip who is sent on a mission during the show. Actor Dane DeHaan ("The Amazing Spider-Man 2") plays Trip in the film. There is a distinct storyline woven through the concert footage, but singer/guitarist James Hetfield confirmed that there is no dialogue involved. The front man wouldn't elaborate on the plot any further, but did say that a lot of thought went into creating the exact right film for Metallica.
"People have done live concerts," Hetfield told CNN before the band's Comic-Con panel. "We've done live concerts and DVDs. If we're going to invest a lot of time and money and effort into something, let's make it unique. That's what we've always done. We had a ton of ideas for this thing. You get really creative with something way out of your budget and then you shrink it down. Some of the best ideas hang on and end up in the film. We wanted animation, we wanted CGI -- you name it! But I think the narrative is extremely potent and multilayered. There's a lot of dynamics going on at once. It's a couple movies in one."
"Through the Never," which opens September 27, has been rated R, which should give fans a sense of what's to come from the film. The footage revealed Friday during the panel included people rioting in the streets, a public hanging, bloody handprints and giant coffins dangling above the stage. The actual concert footage showcases a massive stage with extensive visual effects, including pyrotechnics. Hetfield hinted during the panel that Metallica may eventually bring that stage setup on tour.
Following the panel, Metallica played the 1,500-capacity venue Spreckels, performing crowd pleasers like "Seek and Destroy," "Enter Sandman" and even the "Star Wars" theme and "Darth Vader's Imperial March." Actor Bradley Cooper and football player Drew Brees were in attendance.
Although the focus for the band is on promoting the film, they are slowly still working on a new album as well, which would be Metallica's first since 2008's "Death Magnetic." Hetfield was hesitant to offer any details about the music, however.
"Right now we're doing the movie," he said. "When we're able to focus [on our album] we'll do that."