True Education by My Billionaire Teacher

Plot: Hee-jin, the daughter of a conglomerate family, witnesses school violence and corruption among the adults. Determined to set things right, she goes undercover as a temporary teacher. As she investigates the main perpetrator Jae-young and the principal and vice principal who protect him, she uncovers scholarship fraud and rigged art competitions. Will Hee-jin bring them down and restore justice?