A concubine’s daughter, who was mentally handicapped, inadvertently witnessed her sister’s adultery, which resulted in her miserable death. The moment she stopped breathing, a secret agent, who traveled through time from the modern society, reincarnated in her body. When she opened her eyes again, she was no longer the coward whom everyone could trample on at will. On her following journey of avenging her own misfortune, fighting against the powerful as well as protecting her mother whose life was tantamount to a living hell in the Mu’s Mansion, a bossy, handsome man accidentally intruded on her life…