Our Universe is an infinitely large multidimensional crystal, each face of which is a separate world, with its own history, geography, and its own passage of time. You can move between the worlds of the Great Crystal, for example, using a road that goes through all the Facets. And children with special abilities - koivo - can travel from world to world. The heroes of Vladislav Krapivin will have to endure many adventures, unexpected encounters, and deadly situations in different worlds and times, but true friendship, courage and purity of motives will help them overcome any adversity!