Cho Yeo Hwa has been a widow for 15 years. Her in-laws are the most prestigious noble family in the kingdom. During the day, she leads the life of a widow devoted entirely to her dead husband's memory and rarely ventures outside the gate of her home. At night, Yeo Hwa dons the mask of Hero, who secretly jumps over the surrounding wall to save the helpless.

Trapped in a deadly cursed Mafia game, the students of Yoo-il High must play the game to survive while unraveling the mysteries behind the curse.

A former medical school dropout claiming to be able to cure terminal illnesses is sentenced to death for the murder of 17 people. Is he a monstrous killer, or a savior holding the cure for humanity?