Ruby is a servant girl in a certain town. She doesn't know how she came to be alive, but then a voice in her head calls out to her, urging her to take a test from the "Lady Monsters" to awaken her "Shifting" power. This power allows Ruby to transform into cute and sexy monster girls, and use their powers to solve situations. While the story may seem normal, like a typical self-discovery test, is it really what it is?