This book, the last of three, contains the two final Oz-inspired "Magic Land" stories of the six written by Russian author Alexander Volkov (1891-1977). In "The Yellow Fog," an extremely wicked giantess-witch named Arachna tries to take control of Magic Land, and when the inhabitants refuse to submit to her, she unleashes a dreadful yellow fog on them. "The Mystery of the Deserted Castle" tells of some extraterrestrials from the planet Rameria who come to Earth with the idea of conquering it, and everything possible goes wrong with their grandiose plans!