When the eldest sister got married and eloped, the concubine Liu Mianmian was forced to marry Jin Wang Xiao Jin on her behalf. She thought she was just going to be a substitute until her eldest sister returned and took money to leave, but she was silently favored by the Jin King during the relationship. From guarding her money carefully to falling in love with her, she thought her love was all because of her sister-in-law, but little did she know that King Jin was in love with her from the beginning to the end. A sweet love that goes both ways makes the substitute the only one in my heart.