when wendy, or son seungwan steps her foot back into the school hallways for the first time since summer break, she begins to notice an all-too familiar face, leaving her to wander if she had once knew him- perhaps in her previous life. with the help of her close friends, wendy begins to unravel the true identity of the mysterious new student, not long before they all get themselves into a sticky situation, in other words- a love triangle.