Injun, who returns from studying abroad, is heartbroken to hear that his (ex-)lover, Saein, was imprinted by Jaekyung, who is rumored to be promiscuous bastard. While walking away from Injun toward Jaekyung, Saein does not see a huge truck near him. Injun and Jaekyung, who threw themselves to save him, are caught in an accident. After not waking up for a long time, Injun woke up and was shocked to see his own face in the mirror...that he's now in Jaekyung body!!