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.

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

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.

Dong-eun's end game comes into focus as she sends Jae-jun a troubling package and orchestrates a plan to take down Yeon-jin and Lee Sa-ra.