During the wartime occupation, genius spy Park Eun-mi is shot by the Japanese army, leaving behind a young son. Eighty years later, she awakens in the body of an 18-year-old high school girl during a gala for the Inha Group. Eun-mi discovers that the group's chairman, Lee Jae-young, is her own son, but he lies unconscious in a hospital bed. As she displays genius abilities and secret knowledge of the conglomerate, the chairman's power-hungry eldest son, Lee Ji-hyuk, and delinquent youngest son, Lee Dong-bin, grow suspicious of her. Amidst the family turmoil, Eun-mi rushes to be by her son's side as news arrives that Jae-young is finally waking up.
