During World War II, a group of experienced Polish pilots escapes Nazi-occupied Poland and makes their way to Britain. Despite initial skepticism and resistance from the Royal Air Force, these skilled aviators are determined to contribute to the war effort and avenge their fallen homeland. Their persistence pays off when they are finally given a chance to prove their mettle and are assigned to RAF Squadron 303. Facing not only the looming threat of German Luftwaffe but also cultural and language barriers, the Polish pilots begin intense training sessions.

Amid the fierce Battle of Britain, the squadron's effectiveness and bravery soon become evident as they engage in critical aerial combat missions against the Axis powers. The personal stakes are high for each member of the squadron, dealing with their own struggles, sacrifices, and bonds formed during the heat of battle. As they confront daunting challenges in the sky, they also earn increasing respect and admiration from their British counterparts. The pilots' relentless spirit mirrors the broader struggle for freedom and justice during one of history's darkest times.