Podkayne of Mars whisks readers away to the red planet in a distant future, where Mars and Venus, once mere colonies of Earth, have broken away to claim their independence. At the heart of this cosmic adventure is Podkayne Freis, a spirited young protagonist and the storyteller of this tale, who is brimming with anticipation for her family’s imminent journey to Earth. Her excitement, however, is abruptly shattered when her parents are forced to remain behind to care for three of their babies, unexpectedly released from a facility where they had been kept in suspended animation. Enter Uncle Tom, Podkayne's cherished relative, who steps in to accompany her and her brother Clark on this interplanetary voyage. Unbeknownst to the siblings, Uncle Tom carries a hidden agenda as a clandestine ambassador, tasked with attending a pivotal conference that will decide the fate of Mars and Venus—whether they should join Earth's planetary federation. Uncle Tom firmly believes that Mars should chart its own course, standing apart from the federation in steadfast neutrality.

Aboard a lavish space cruiser setting course first for Venus, Poddy embarks on a series of thrilling escapades. She forges new friendships, flirts playfully with the ship's crew, and gallantly proves her mettle when a perilous radiation storm threatens their journey. As the narrative unfolds on Venus, Poddy and Clark find themselves ensnared in the web of political maneuvers surrounding Uncle Tom's critical mission, where the stakes are as high as the stars themselves.