Upon dying, Dani appears in the world of YYH—a warped world in which North America has ceased to exist. Distrusted by the characters she's trying to aid, Dani must prevent the dire future an alternate version of Koenma warned her about... but that's not easy when you have no allies, no fighting skills, and people have a nasty habit of lying to your face every three seconds.[HieiOC]

Fireflies are elusive, mysterious beings, something meant to fly wherever it pleases, bringing its beauty to those who appreciate it. Such a beautiful, fragile creature could not survive in a captive lifestyle. And so I set him free, my human firefly.