Nana, is a young girl who unexpectanly aquires super natural powers and at the same time loses her past memory. By accident, a scientic genius called Marlow, is present when she acquires her powers. Marlow is an industrious high school boy with extraordinary ambitions. He talks to Nana into joining his detective agency by promising to help her regain her memory. Nana innocently believes him, but Marlow's real intent is to use her power s to benefit his agency and himself.
The story unfolds as Nana encounters a veriety of dangerous missions and mysterious events, but her natural sunny dispotion helps her through all the incidents as she solves each mystery one after the other.