In one of Morinaga's earlier and more somber creations, Mare is a enigmatic young girl with the ability to call forth monsters. She arrives at a high school seeking out individuals entangled in relationships marked by envy, animosity, rage, and longing, aiming to uncover injustices and mete out her unique form of retribution. As Mare's true intentions unfold, what obstacles will she face, and how will the students she encounters be affected by her presence?