Magical Gosamjeu

A girl named Yeo-Reum Han begins her last year of high school following the death of her older sister. During a long nap in class, she awakens to see her biology teacher and her best friend dressed in cosplay and battling monsters. Confronted by danger, Yeo-Reum decides to become a magical girl and seeks the truth about her sister's suicide. As the SATs approach, she must balance her responsibilities while trying to preserve peace and love in the world.