Psychology professor Eun Soo-hyun (Kim Nam-joo) originally had a beautiful life and a successful career that everyone yearns for, but after her young son was innocently killed, her life changed forever and she embarked on a tragic road of revenge. During this period, she met a medical dropout, Kwon Sun-yul (Cha Eun-woo). The two who experienced similar misfortunes tried to uncover the truth of the incident together and heal each other's pain.