Kirara Asai, 24, dies in a car accident en route to her wedding with Konpei Asai. She returns as a ghost eight years into the past, manifesting naked beside the 16-year-old Konpei while her past self is 18. Invisible to all except the teenage Konpei, her initial appearance frightens him.

This ghost retains vivid memories of her six-year romantic relationship with Konpei preceding her death. Despite this established history, she deliberately intervenes in the past, actively seducing the younger Konpei to take his virginity. Her actions starkly oppose her 18-year-old human counterpart, who embodies seriousness, duty, and reserve. The ghost Kirara displays a playful, mischievous, and uninhibited nature, frequently appearing provocatively dressed or nude to unsettle Konpei. She exhibits no shame, openly flirting with him during classes and in public.

However, her boldness fades outside Konpei's presence, revealing insecurity and timid reactions to unexpected social encounters reminiscent of an inexperienced schoolgirl. The opposing personalities of the ghost and her younger human self lead to constant conflict between the two Kiraras.

As a ghost, she possesses no sense of taste, rendering her unable to cook or bake effectively. She also bears a physical vulnerability: a gentle blow into her ear causes complete loss of strength. Her ultimate fate remains unresolved at the story's conclusion, leaving her existence ambiguous—whether she vanishes, forms a ménage à trois with her younger self and Konpei, or persists as a spirit.