Synopsis：Adopted by the Namgung family, Namgung Byeol once lived a happy life, loved by her three older brothers. However, everything changes when the family's biological daughter, Namgung Dal, returns home. Disheartened by repeated misunderstandings and neglect over the two years that the biological daughter has been present, Namgung Byeol secretly volunteers for her eldest brother's scientific project, the "Star Sleep Project" in order to repay her brothers' kindness.