Bom Do, a timid middle school student, can never say no to people because she is afraid of being disliked. Her only confidant is her grandmother, an extroverted woman who raised her and her sister. One day, Bom's grandmother wakes up in her granddaughter's body after getting into an accident. Can the grandmother, who is the polar opposite of her granddaughter, adapt to school life while she looks for a way to return to her body?