Jun Yagami, a 16-year-old Earth girl, pursues her spaceship license to launch a solo mission across the stars. Her singular goal: finding her missing father, Mamoru Yagami, leader of the vanished Paratopia exploration team. She carries her father's laser gun as a talisman throughout her search.

A violent space storm forces her spacecraft down onto Kirakira Planet. There, the peaceful Senobi tribe rescues her. Hailed under an ancient Senobi legend as "a cute girl who came down from the sky on a certain date to bring happiness to the Senobi Tribe," she gains their warm acceptance.

While staying with the Senobi, Jun faces repeated threats. The hostile Robot Tribe, manipulated by the Kariage family, attempts to capture her. She finds rescue each time in Starzan S, a young man with superhuman abilities residing in the planet's forests. Jun develops admiration for him, initially unaware of his Earth origins or connection to her quest.

Her arrival indirectly sparks crucial revelations. Starzan S is exposed as an Earthling baby who accompanied his parents on the very same Paratopia mission as her father. Additionally, Darth Bello, leader of the Robot Tribe, is uncovered as the missing husband of Maneko Kariage, linking the Kariage family's actions directly to Jun's journey.

Back on Earth, Jun's mother, Yoko Yagami, awaits her daughter's return. Their eventual reunion plays a key role in confirming Starzan S's Earth origins and uncovering the shared history between their families.