In the summer of 1940, the RAF hastily assembles the 303 squadron made up exclusively of Polish airmen, who have made their way across the English Channel following the Nazi invasion of their homeland. Ace pilot Jan Zumbach is among the brave recruits, who arrives in Britain with a broken heart, believing his sweetheart Jagoda is trapped in their invaded homeland. Jan dedicates himself to supporting the British pilots against the Luftwaffe onslaught.