Tormented by her high-school classmates and with nowhere to turn for help, Moon Dong-eun sinks into despair before deciding on a new mission in life.

With Park Yeon-jin's wedding on the way, Dong-eun's revenge rolls out according to plan. Meanwhile, a fateful encounter at a hospital transpires.

After securing the services of an amateur sleuth, Dong-eun uncovers scandalous secrets that she leverages for the next phase of her scheme.

Yeon-jin, who was already nervous about the resurfacing of the past, becomes even more anxious when she learns of her daughter's new teacher and a sudden death.

As Ha Do-yeong encounters a scheming opponent in the game, Yeon-jin realizes that her deepest secrets are at stake when she tries to intimidate Dong-eun.

Son Myeong-o's sudden absence causes tensions in the group of friends; Dong-eun's trust in Kang Hyeon-nam is put to the test.

Dong-eun shares her traumatic past with Joo Yeo-jeong, who has his own unfinished business; a new plan is set in motion for Hyeon-nam's daughter.

Do-yeong meets Choi Hye-jeong to learn more about his wife and his past; Yeon-jin digs into Dong-eun's private life.