Chances are, if you've seen Keira Knightley onscreen since her breakout in 2005, you've watched her star in a costume drama or period piece. (Between two of her most famous films, Pride & Prejudice and Atonement, alone, she's covered practically the entire 19th century.) And yet, judging from the trailer released on Wednesday, her latest film, Official Secrets, doesn't feature a single corset; having jumped the action forward a century or two, the film has her dressed in an entirely different British dress code—and a rather drab one, at that.

Based on a true story, Official Secrets stars Knightley as Katharine Gun, the whistleblower who helped expose the U.S. and U.K. governments' apparent plans to sway the United Nations into supporting an invasion of Iraq by leaking a key email to the press. As it did in real life, that all goes down in 2003, which is also essentially when the government and public ceased to care about the matter. (As director Gavin Hood noted to the Guardian, Gun wasn't even asked to testify in the U.K.'s recent Iraq Inquiry.)

For those who've since forgotten about Gun—or members of Gen Z, who might argue that the a film set in the early aughts still falls under the umbrella of a period piece—a quick recap: Gun, then 28, was working as a Mandarin translator for the Government Communications Headquarters (GCHQ) when she came across a letter from the NSA, asking the British to help with their efforts to get a U.N. resolution for war. Ignoring a warning that doing so could qualify as treason, she passed it along to a journalist, played in the film by Matt Smith, who in turn passed it along to the public via the front page of the Observer, under the headline "Revealed: U.S. Dirty Tricks to Win Vote on Iraq War."

Naturally, that didn't go over too well with the authorities. "Someone has betrayed the government and their country," the GCHQ tells its employees in the trailer. Before long, cops are escorting Knightley into a cell, and accusing her, during an interrogation, of both being a spy and working for the British government. "No, I work for the British people," she retorts. "I do not gather intelligence so that the government can lie to the British people."

Gun is soon charged with violating the Official Secrets Act, but from there, she only grows more fiery—particularly when the government insists on also investigating her husband (Adam Bakri), suspecting that he was involved simply because "he's a Muslim." Luckily, a lawyer, played by Ralph Fiennes, seems to come to Gun's rescue. If you can't wait until August to determine whether or not he succeeds, well, it's time to make like Gun and start digging.


Related: Keira Knightley Speaks Out About Her Mental Breakdown and the "Violence" of Early-2000s Paparazzi