Modern worker Lin Xuan accidentally transmigrates into a rusty demonic sword. On the verge of being melted down, he is subdued through a blood pact by Su Qinghan, the fallen young lady of a ruined clan. With her meridians completely shattered and carrying a deep blood feud, Su Qinghan drunkenly kills an enemy by mistake, accidentally activating the Demonic Sword Evolution System: killing enemies allows her cultivation to advance. Together, the two hunt ferocious beasts and slay enemies, transforming the demonic sword from a rusty blade into a divine weapon, while Su Qinghan's meridians gradually recover. Facing the attack of the mastermind behind the scenes, Su Qinghan grows stronger with every battle, ultimately achieving human-sword unity with Lin Xuan to execute the enemies with her own hands and clear the grievances of the entire Su family.