The film is based on the autobiographical story of the famous Estonian children's writer Eno Rauda "Fire in a darkened city. The action takes place in the years of the Great Patriotic War in a small Estonian town and tells how three schoolchildren - Hulot, Olev and Heldur - helped the grown-ups fight the German invaders and their henchmen. The boys managed to expose the provocateur - a local resident, who gave the fascists a family of Red Army men. And on the day of the six hundredth anniversary of the Estonian uprising against the German feudal lords - April 23, 1943 - the guys decided to light a bonfire on the ruins of an ancient castle in a sign that Estonia did not submit to fascism, that the struggle continues and the hour of liberation is near ...