Yeorum Han traumatized by Gyeowul's (her older sister) death. She committed suicide by jumping from her high school's roof top. One day, Yeorum witnesses her male biology teacher in a magical girl's dress fighting giant fish at school. Yeorum recieves her sister's magical girl's item and avoids danger by transforming into a magical girl. With SATs approaching closer and closer, can she protect the love and peace in this world? A tale about Han-Yurem, who became a magical girl in her 3rd year of high school, and the mysteries that surround her. (Source: WEBTOONS)