Momo hails from Marinarsa, an undersea kingdom of dreams and fairy tale characters threatened by humanity's fading hopes. Sent to Earth by her royal parents, she is adopted by a childless couple, appearing as a young girl accompanied by three animal companions: Cookbook the dog, Lupipi the bird, and Charmo the monkey.

Her task involves harnessing magic to transform into an adult, assuming professions like police officer, veterinarian, or theme park programmer to solve human problems and restore dreams, thereby stabilizing Marinarsa. Initially, her magic is limited, depleted from her journey, but later expands to include spellcasting and diverse forms for broader societal issues.

As the series progresses, Momo and her family become refugees amidst widespread despair. She meets the original Momo from Fenarinarsa, the sky kingdom, confirming shared continuity. Despite their collaboration, magic and fairy tale beings vanish as human disconnection deepens. Facing Marinarsa's imminent departure, she chooses to stay on Earth permanently, relinquishing her royalty to become her adoptive parents' biological child, fulfilling their dream of family.

In later OVAs, Momo appears in human-centric stories. *Minky Momo in The Bridge Over Dreams* sees her upholding a local legend by repeatedly meeting a skeptical boy on a bridge, impacting others who cross it. *Minky Momo in The Station of Your Memories* depicts her aiding an elderly man seeking a lost connection at a train station; there, she encounters a parallel version of herself and helps a young girl resolve emotional ties to the location, emphasizing her role as a catalyst for human connections without magic.

A third incarnation, the princess of Leafinasa, was conceived for the manga *Miracle Dream Minky Momo* but remained unrealized in anime due to creator Takeshi Shudo's death in 2010.