This world called "Rare World" is a dimensional fragment.
In "Rare World", there is a street called "Cheyun". "Cheyun" exists like a city called "Ikebukuro" in another world.
And "Cheyun", like "Ikebukuro", among most ordinary humans, there are always a few exceptions.
A girl with multiple identities, a will-o'-the-wisp floating on the street, a "rare" wanted criminal - the murderer "Dark Execution", a genius-level flower who spends all day with electronic products, a mysterious organization...
Everything originates from this world.