Reinya appears to be an ordinary girl working at a convenience store but that is nothing but a disguise for her secret identity as Phantom Thief Reinya. Together with her assistant Chūtarō in their secret hideout right below the local convenience store, Reinya hatches plans to steal various treasures made of gold. They face an incompetent trio of a perverted police inspector, a policewoman who is a natural airhead, and a detective totally infatuated with Reinya, all of them in a police station right beside Reinya's convenience store.
