Eleven-year-old Xiao Yu, a transmigrated girl with a deadly secret, survives in the brutal Flowing Sands Domain by adopting fathers—only for them to die shortly after she calls them 'Dad.' Her mysterious ability, 'Big Annihilation Dad,' lets her identify and exploit the fatal flaw in any martial cultivator who acknowledges her as a daughter, but her own physical strength is too weak to execute the kills reliably. As she navigates a world where the Qin Dynasty’s martial virtues have reached supernatural heights and weak water defies the laws of physics, she seeks a powerful enough father to survive her next encounter.

When she encounters the enigmatic Guan Huchen, a legendary warrior with a tragic past and hidden divine lineage, she sees her best chance yet—but will he be the one to die… or the one who saves her? With every adoption, the world grows more dangerous, and her past begins to unravel in ways even 'Big Annihilation Dad' cannot predict.