Shen Zhiwei secretly harbored a crush on Fu Yunchuan for many years, but out of insecurity, she wrote love letters for her best friend Xie Yiwen to pursue him. By a twist of fate, after ending up with Fu Yunchuan and giving birth to their daughter Tiantian, the two maintained a four-year underground relationship. After Xie Yiwen returned to China, Shen Zhiwei resignedly stepped down, yet amidst heavy crises such as a mystery surrounding her birth, her daughter's serious illness, and her best friend's frame-ups, she endured life-and-death tests with Fu Yunchuan, ultimately uncovering the truth and reuniting.