Once known for ruling her school with a single punch, Mina is a fiercely righteous girl who lost her parents in a childhood accident and was raised by her aunt. Entering high school with a promise never to fight again, she hopes for a normal fresh start but finds herself drawn to her seatmate Min ki from the very first day. When Min ki becomes the target of Se hyeok, the leader of a delinquent clique, Mina intervenes by rescuing him while disguised in a tracksuit with her face covered. The incident throws the school into turmoil as students search for the identity of the mysterious rescuer and Min ki begins his own pursuit of the truth. As tensions rise around Min ki, Mina struggles to hide her identity while maintaining an increasingly unstable everyday life.