Moon Dong-Eun's (Song Hye-Kyo) silent fury against those students that horrifically abused her during her high school years continues to burn inside of her. She meticulously executes her plan to inflict ultimate pain on her tormenters. Meanwhile, the sudden disappearance of Son Myeong-O (Kim Gun-Woo) has gotten the attention of the police and his friends. Joo Yeo-Jeong (Lee Do-Hyun) follows Moon Dong-Eun and is willing to do anything she asks in her pursuit of revenge. Before Moon Dong-Eun begins her final moves, she offers her nemesis Park Yeon-Jin (Lim Ji-Yeon) a chance to save herself if she turns herself into the police, but Park Yeon-Jin has her own plans to stop Moon Dong-Eun. A violent and bloody game of nerves plays out between these rivals.