As in his 2015 thriller Eye in the Sky, about the harrowing calculations behind drone war strikes, director Gavin Hood relies on the narrative device of a ticking-clock countdown in this adaptation of Marcia and Thomas Mitchell’s espionage chronicle The Spy Who Tried to Stop a War: Katharine Gun and the Secret Plot to Sanction the Iraq Invasion. Keira Knightley stars as Gun, a British information analyst and translator at the intelligence agency Government Communications Headquarters, who became a whistle-blower in 2003 after receiving an e-mail request from an American NSA operative to strong-arm less powerful members of the UN into voting for an invasion of Iraq. When she leaks the document to London’s the Observer, the movie becomes a solid newspaper yarn as well as a political caper, as three reporters (Matt Smith, Rhys Ifans, and Matthew Goode) race to expose the U.S.-British collusion and avert war. Their efforts did not prevent the invasion, and so suspense arises from the personal peril Gun and her husband (Adam Bakri) experience as she’s targeted for violating the Official Secrets Act. It’s in this half of the picture where Knightley shines brightest, in a performance that balances conviction and soul baring, and is all the more genuine for its lack of showiness. With Ralph Fiennes and Conleth Hill.