In 2003, just before the invasion of Iraq breaks out, a British intelligence analyst named Katharine Gun finds herself caught in an overwhelming moral dilemma. After receiving a leaked memo from the NSA revealing a secret plan to spy on UN members in order to manipulate their decisions regarding the war, Katharine is faced with a choice that could change everything. Aware of the implications of this information, she decides to risk it all and leaks the document to a journalist, triggering a media storm that shakes the foundations of the British government and public opinion.
As the story unfolds, Katharine becomes the target of personal and professional attacks. Her life transforms into a dark legal battle as she struggles to protect herself from reprisals while simultaneously bringing the truth to light. The pressure mounts when she realizes that her choice affects not only her, but also her family and friends, who are drawn into this maelstrom.
Through an intense and revealing narrative, the film depicts the personal cost of doing what is right in the face of a corrupt system. Katharine becomes a symbol of resistance and courage, raising profound questions about loyalty, truth, and the complexities of morality in times of war. The tension escalates as it is based on true events, forcing the viewer to reflect on what it means to be a true agent of change.