The dog is named Sirius and plays hide and seek w/ the boy. The boy hides and the dog comes to find him. The Nazis take over and the boy and an older man are worried the dog will be taken and trained to harm people. They decide they must destroy him, so the boy hides and whistles for the dog, and the man shoots him as he is running. Very sad. Not sure if it is set in France or Czechoslovakia or where... European countryside setting...