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.

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.

Do-yeong meets with Choi Hye-jeong to find out more about his wife — and her past. Yeon-jin digs into Dong-eun’s private life.

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.

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.

Do-yeong issues an ultimatum. Dong-eun demands a piece of evidence be handed over. Yeon-jin attempts to do damage control after old videos appear online.

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.