The Island on Bird Street (1997) on Netflix

During World War II a Jewish boy is left on his own for months in a ruined house in the Warsaw Ghetto, where he must learn all the tricks of survival under constantly life-threatening conditions.

Alex is an 11-year old boy who, during WWII, hides in the Jewish ghetto from Nazis after all the relatives have been sent to the concentration camp. The movie portrays the ghetto through his eyes.

—Anonymous

During World War II, twelve year old Alex, his father Stefan, their Uncle Boruch and Alex's pet mouse Snow live in Warsaw in the Jewish ghetto, around which the Nazis have erected a fence so that no one can get out. The Polish Jews live their daily lives in the bombed out ghetto, but go into hiding whenever the Nazi soldiers come for what they call the selection process when truckloads of Jews are hauled away to an unknown future. Alex's family is one of the last in the ghetto, when the Nazis come to haul all remaining Jews away. Previously discussed amongst themselves, Alex manages to escape from the Nazis before he can be taken away. Alex is supposed to hide in the ghetto, with Stefan vowing that he will eventually come back for him. As Alex lives alone in the ghetto, he has to use his resourcefulness to find food and potable water, and to find a suitable hiding place for whenever the Nazis come looking for any remaining Jews. He also has to assess who he can and cannot trust amongst the handful of remaining people who are also hiding out in the ghetto. After he meets and befriends two other hiding Jews named Freddy and Henryk, Alex is shown a secret tunnel leading out of the ghetto into unfenced Warsaw. Alex has to make the decision to go to the safer unfenced zone, where the likelihood of ever seeing Stefan again is slim to none, or to stay in the ghetto and the thought of reuniting with Stefan but with the understanding that the Nazis will eventually demolish the ghetto.

—Huggo

Alex is an 11-year-old Jewish boy living in a Ghetto in German-occupied Poland during World War II with his father and their friend, Boruch. German soldiers come into the Ghetto and send people into trains to be taken away "most likely to concentration camps". Alex and his father get separated, and soon Alex has to learn how to kill time in the empty ghetto by himself. As it turns out the ghetto is not entirely empty, and that is where he comes across various people, from neighbors to robbers, some of whom even try to help him. He finds himself in an abandoned, bombed out building on Bird Street "Ptasia street" where he seeks refuge. The only thing he has to pass the time away with is his pet mouse Snow, the novel Robinson Crusoe and other books, and a small window overlooking the town. He has to hunt for food on his own and still stay hidden from soldiers. It is a great test for Alex to see if he can make it through tough conditions, and also wait for the arrival of his father.

—yusufpiskin