Kostya Peremenkin is an ordinary boy. He lives in an ordinary city with his mother and father, studies in an ordinary school and recently entered third grade. Kostya loves to play with friends, travel with his parents, ride a bike, watch funny videos on the Internet - in general, what all the guys love. Kostya is also very inquisitive. He loves to ask questions, which are answered by mom, dad, teachers and others. Together with Kostya, little readers will learn why it is cold at the South Pole, why astronomers need mathematics, where holes in cheese come from, who came up with the idea of decorating a Christmas tree for the New Year, and much more.