Yume Yume * You You narrates the story of a girl named Yume who has a twin sister stealing all the limelight. Yume considers herself inferior as her sister is more famous, intelligent, and attractive.
While not putting much effort into her studies, Yume stumbles upon a peculiar mirror that summons beings from other dimensions into her realm! To rescue both worlds, Yume has to become Kagura Yume and take on the challenge!