After being appointed as the vice-principal of her alma mater, Eun-hee becomes plagued by hallucinations. Branded a troublemaker by the teachers, Ha-young hears strange sounds coming from the school's dilapidated restroom.
| Actor | Role |
|---|---|
 Kim Seo-hyungEun-hee | Eun-hee |
 Kim Hyeon-sooHa-young | Ha-young |
 Choi RiSo-yeon | So-yeon |
 BIBIYoung Eun-hee | Young Eun-hee |
 Seo Hye-wonMi-sook | Mi-sook |
 Park Se-hyunJae-yeon | Jae-yeon |
 Lee Ji-wonYe-ji | Ye-ji |
 Jang Won-hyungPark Yeon-mook | Park Yeon-mook |
 Kwon Hae-hyoBae Kwang-mo | Bae Kwang-mo |
 Lee Joo-silGrandmother | Grandmother |
 Chae Won-binClassmate | Classmate |
 Ha MinKim Jung-yeon | Kim Jung-yeon |
| KKim Sung-nyeoSeok Gong-nyeo | Seok Gong-nyeo |
 Shin Yeon-miChoi Ji-hee | Choi Ji-hee |
 Min Chae-yeonKim Hong-ran | Kim Hong-ran |
| PPark Yun-hoNam Sang-taek | Nam Sang-taek |
| SSung Gyu-chanPolice | Police |
 Yoon Jung-wookInvestigator Nam | Investigator Nam |
 Ko Guk-heeHigh School Student | High School Student |
| MMoon Gyeong-huiMun-jung's mother | Mun-jung's mother |