Su Qingyue, raised by her royal uncle Xiao Mohan, falls deeply in love with him—only to be rejected when she confesses. When the Xiongnu invade and demand a princess in exchange for peace, Su Qingyue volunteers to marry their leader, secretly planning to assassinate him. She succeeds but is killed in retaliation. The King of Hell, moved by her sacrifice, grants her seven days to settle unfinished business in the mortal realm. Returning to the palace, she witnesses Xiao Mohan in bed with another woman, Xu Wan’er. He accuses Su Qingyue of cowardice, unaware she’s a ghost. Heartbroken, she recalls his childhood promise to always protect her—now broken. As she tries to sever their bond, Xiao Mohan learns the truth about her assassination of the Xiongnu leader but still sides with Xu Wan’er, even whipping Su Qingyue when she refuses to kneel in apology. Clues emerge—Xiao Mohan’s headaches ease only with Su Qingyue’s handmade incense; Xu Wan’er is exposed for stealing her remedies. Yet Xia