Yoshida Yuko, living an ordinary yet impoverished life, undergoes a startling transformation at fifteen when demon horns and a tail emerge. Unveiling her true identity as Shadow Mistress Yuko, a demon bound by a curse of perpetual poverty, she learns that defeating her schoolmate, the formidable magical girl Chiyoda Momo, is the key to breaking the curse. Despite Momo's superior strength, magical prowess, and kindness towards Yuko, the demon struggles to overcome her and fulfill her goal. With a dilemma between friendship and familial redemption, Yuko must navigate the complexities of her newfound powers and alliances in a quest to liberate her family from the curse.