Summer holidays are the best time for traveling, impressions, and discoveries, so two sisters Aster and Stella go to the Carpathians to admire the starry sky, which fascinates and makes the younger sister curious about stars. The young scientist Aster will help Stella discover the nature of stars. How distant are the stars? How are they born, and how long do they exist? Which stars are the hottest? How are black holes formed? And what will be the future of the Sun?