Kim Yoo-jin

Widow Ok is the daughter-in-law of the Hwang family in Youngnam region, a family known for its generations of virtuous women. Widow Ok sticks to a life of principles and focuses on rearing her children. Chon-seok is a servant who has feelings for Ok but is resigned to admire from afar. Choi, a man of influence, has his eyes on Ok and wants to get rid of Chon-seok.

A boy falls to his death at school, but Ok Chan-mi does not believe that her twin brother, Park Won-seok, committed suicide. Chan-mi transfers to her brother's school, Yongtan High, and meets Ji Soo-heon, who witnessed her brother's death. A "hero," who avenges bullied students, appears at Yongtan High. Chan-mi speculates that it may be connected to her brother and starts looking for this hero.