Song Zhiyi, the biological daughter of the Song family who was separated from them for twelve years, finally returns home to reunite with her family. However, she is constantly mistreated by her biological mother, Song Yunshu. After her mother's death, all she leaves behind is a single final sentence, plunging Zhiyi into despair. What she doesn't know is that those words are actually part of a protective plan her mother devised with her own life. Through the final words and a key her mother left behind, Song Zhiyi gradually understands the protection hidden behind her mother's apparent coldness. When faced with the adopted daughter's schemes and her biological father's calculations, Zhiyi refuses to back down. Using the clues her mother left behind, she strikes back against everyone harboring malicious intentions. A battle concealing a mother's profound love finally begins.