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.

Son Myeong-o’s sudden absence causes tension in the friend group. Dong-eun finds her trust in Kang Hyeon-nam tested.

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.