Valkyrie, a Valhallan princess from the Dolphin Constellation, flees her homeworld to escape a politically motivated marriage, crash-landing on Earth in Kazuto Tokino’s bathhouse. To save his life, she sacrifices half her soul, shrinking into an eight-year-old with a spirited, impulsive personality and an intensely protective attachment to Kazuto, often misinterpreting social cues. Brief physical contact with him temporarily restores her adult form—a poised, wise ruler wielding energy manipulation, flight, and the Key of Time, a sword-like relic of her lineage. Initially usable in both forms, the Key later becomes exclusive to her matured self.

Their evolving romance leads to an engagement repeatedly thwarted by her unstable transformations and external conflicts. A shattered mural splits her into coexisting child and teenage/adult entities, both sharing memories and emotional ties to Kazuto. Observers occasionally mistake the child for her daughter, complicating her dual existence. Allies like Sanada, her devoted maid, and rivals such as Hydra, a fellow Valhallan princess sparking chaotic clashes, punctuate her life. Earth allies include Akina, a shrine maiden harboring quiet feelings for Kazuto, though their friendship remains intact.

Adventures span skirmishes with space pirates, treasure hunts, and ceremonial trials, testing her resilience. Her child self indulges in manga and TV, contrasting her adult form’s regal obligations. Environmental healing on an asteroid mends her soul but destabilizes her physical forms. As the split persists, the child retains playful innocence while the adult juggles sovereignty and personal longing, their unresolved duality lingering as a central challenge in her quest for wholeness.