Meet Nia. Her trainer Xaki is teaching her to be a Biter. She looks up to her trainer, and will do anything for him, including tracking down some Zero Number named Ren! When word gets out that Ren escaped from Xaki when he tried to bring her back to the community, Nia sets out to avenge the dishonor done to her trainer. Meanwhile, Ren is getting more attention from class playboy Hiro, who tries to plant doubt in her mind about the nature of her relationship with her "master." And when Rubi, a DearS dominatrix, begins to mark her territory, could Ren be headed for the recycling bin?