Set in northern China in the 1980s, this story begins on a snowy night eighteen years earlier, when a power outage at a town hospital led to two baby girls born on the same day being accidentally switched. When a serious illness forces the farm girl Lin Sui to undergo a blood test, doubts about her identity come to light. Her adoptive father, Lin Laoshi, travels all the way to the provincial capital, where he finds Lin Sui's biological father, compound official Shen Jianguo. After the truth emerges, Lin Sui moves into the Shen family home in the provincial capital. Shen Man, who grew up in the compound, feels deeply lost as the family's attention shifts and eventually chooses to move into a factory dormitory. Struggling to adjust to their swapped identities, the two girls and their families are torn between blood ties and the bonds forged through years of raising a child. Through everyday conflicts and mutual understanding, they gradually find their way toward reconciliation.