Seventeen-year-old Lin Yuan is a bright, cheerful girl who once fell for her math teacher—only to be left with heartbreak. As she grows up, she learns to let go of the past and move on, though the pain still lingers and keeps her from opening her heart again.

Everything changes when she meets Xiao En, a brilliant but emotionally distant math teacher who reminds her of someone she once knew. Though he's known for his high IQ and low EQ, there’s more to him than meets the eye. As Lin Yuan is drawn to his quiet charm and hidden depth, she begins to fall once more—into a romance that feels strangely familiar. But is this a second chance at love, or something far more mysterious?