After falling in love with genius programmer Jiang Yicheng, Lu Li enrolls into the school he once studied at, and also took up the same major - calculus. Setting Jiang Yicheng as her role model in her heart, she achieves good grades in school. However after graduation, she did not expect that Jiang Yicheng's company does not recruit female employees. Lu Li decides to disguise as a man and enter the company. However, she met difficulty both in dealing with Jiang Yicheng's demands, as well as hiding her identity. Finally with her perseverance, she grabbed hold of an opportunity and managed to come to an agreement with Jiang Yicheng. The two would become a "contract couple" and stay together for one year. Slowly, Jiang Yicheng finds himself falling for Lu Li.