Season 1
A high school student dreams of becoming an architect. However, she had to drop out of school after suffering from brutal school violence. Years later, the perpetrator gets married and has a kid. Once the kid is in elementary school, the former victim becomes her homeroom teacher and starts her thorough revenge towards the perpetrators and bystanders of her bullying days.
01. Episode 1
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.
02. Episode 2
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 takes place.
03. Episode 3
After securing the services of an amateur sleuth, Dong-eun uncovers scandalous secrets that she leverages for the next phase of her scheme.
04. Episode 4
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.
05. Episode 5
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.
06. Episode 6
Son Myeong-o's sudden absence causes tension in the friend group. Dong-eun finds her trust in Kang Hyeon-nam tested.
07. Episode 7
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.
08. Episode 8
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.
09. Episode 9
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.
10. Episode 10
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.
11. Episode 11
Hye-jeong finds an incriminating recording on Myeong-o's tablet, and Hyeon-nam receives an unwelcome visitor as she prepares to send her daughter abroad.
12. Episode 12
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.
13. Episode 13
As Sa-ra and Yeon-jin deal with the aftermath of their crumbling reputations, Dong-eun learns the details behind Yeo-jeong's private struggles.
14. Episode 14
Yeon-jin and Shin Yeong-jun panic over Myeong-o. Dong-eun takes care of a lingering problem. Yeon-jin’s mother schemes to remove a threat.
15. Episode 15
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.
16. Episode 16
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.