Does your child love exciting adventures? What if they are also magical? Then this book is just for him! And it is also about the MOST IMPORTANT thing, which the little hedgehog Seryozhik, who grows tangerine seeds and for the time being was afraid of everything in the world, did not know. He, of course, will become big and brave, as Mom told him, but this will not happen very soon. Difficult roads, dangerous encounters under the ground and in the sky - the path that Serezhika must go through with the Key and the sword. This is a wise and very kind fairy tale about dreams, friendship, loyalty and responsibility. And also that the Key opens all doors if you correctly answer one - the only question: “What is the most important thing in the world?” Seryozhik already knows. And you?