In this exciting science fiction novel for children, readers will go on a journey with brother and sister, Matvey and Lisa, who become space explorers, discovering not only the secrets of the solar system, but also the mysteries of the far corners of the Universe. From their first steps on the Moon and Mars to the deep reaches beyond our galaxy, they encounter ancient civilizations, explore forgotten technologies, and uncover secrets that change the way we understand the structure of time and space. Each chapter of the book takes readers farther away from familiar worlds, immersing them in stories about ancient portals that can instantly transport through galaxies, about the Universal Library storing the knowledge of many civilizations, and about meeting the keepers of time - beings with wisdom that spans eras.