In 1939 Warsaw, Poland, Antonina Żabińska and her husband, Dr. Jan Żabiński, run the Warsaw Zoo. Their idyllic life is shattered by the Nazi invasion, which leads to many animals being killed and the zoo getting partially destroyed. As the war progresses, the Żabińskis are forced to report to Lutz Heck, the Reich's chief zoologist, who has plans to breed a lost species of colossal aurochs within the zoo’s grounds. Under this new administration, the zoo transitions from an institution of conservation into a sinister enterprise that serves the Nazi war effort.

Amidst the turmoil, the Żabińskis become active in the Polish resistance movement. They begin using the zoo as a covert sanctuary for Jews escaping the Warsaw Ghetto. Through careful planning and immense bravery, they manage to rescue hundreds of lives, hiding refugees within the zoo’s abandoned animal cages and their home. Racing against time and under constant threat from Nazi forces, especially Heck, who regularly visits and grows increasingly suspicious, the Żabińskis’ efforts represent a shining example of courage and compassion during one of history's darkest periods.