The book is based on a legend of the northern peoples about the existence of a mysterious warm land in the Arctic Ocean. The blessed island β an oasis among the ice β is covered with forests and meadows in a ring of huge mountains; prehistoric creatures live here: mammoths, saber-toothed tigers, cave bears, and woolly rhinoceroses, and primitive tribes dwell there as well.
Although Sannikov Land does not actually exist, Obruchev substantiates from a scientific point of view the possibility of a warm island existing in the realm of permafrost. Thrilling adventures are combined with a detailed description of the surrounding nature, soil structure and wildlife, and the life and customs of native peoples.