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.

Already on edge over the past resurfacing, Yeon-jin grows more anxious when she learns about her daughter's new homeroom teacher — and of a sudden death.

While Ha Do-yeong comes across an intriguing game opponent, Yeon-jin realizes her deepest secrets are at stake when she tries to intimidate Dong-eun.

Dong-eun shares her traumatic past with Joo Yeo-jeong, who has unfinished business of his own. A new plan is put in place for Hyeon-nam’s daughter.

Questions arise over Myeong-o, Dong-eun gives Yeon-jin a chance to come clean about her past, and the circumstances of Yoon So-hee's death are revealed.

Yeon-jin threatens Hyeon-nam after discovering her involvement with Dong-eun. Yeo-jeong devises a way to get the truth out of Yeon-jin.

As the final pieces of Dong-eun's revenge plot slot into place, she considers what comes next — and what it will mean for Yeo-jeong.