Follows the story of Ok Chan-mi as she seeks revenge for the death of her twin brother.
Genre: Drama, Mystery, Thriller
Cast:Shin Ye-eun , Park Solomon , Seo Ji-Hoon , Sang-woo Chae , Lee Soo-min , Su-bin Chung , Kim Joo-Ryung , Kang Yul , Yeon Oh , Wooyeon , Ho-Eun Jin , Han Seung-Bin , Hwang Bo-Un , Jinwook Ok , Harrison Xu , Eugene Ko , Ren Hanami , Jolene Kim
Ok Chan Mi does not believe that Park Wong Seok killed himself and believes the culprit is still at the school.
Soo Heon is suspicious of Chan Mi's feigned unfamiliarity with Park Won Seok. Chan Mi learns a shockingly different Won Seok from Lim So Mi' portrayal.
Soo Heon punishes Sa Jung Kyung and is called a hero by the students, but Chan Mi grows suspicious.
There is a scheme to kick Chan Mi out of school, and Soo Heon advises her to leave.
Won Seok's case is reclassified as a homicide. Chan Mi learns Won Seok's lie to her.
Soo Heon finds himself in a predicament as he becomes the number one suspect of a murder.
Chan Mi gets an unbelievable call, as she holds Soo Heon at gunpoint.
Chan Mi and Soo Heon are convinced that Gi O Sung is Won Seok's killer.
Chan Mi is confused when she sees the polaroid photos that Soo Heon stole from O Sung's room. Ah Jung connects Min Seon Ha's father and Soo Heon.
O Sung's plan to catch Soo Heon fails. Chan Mi and Jae Beom set up a trap to feel out Gi O Sung, but they discover a shocking truth.
Jae Beom regains his memories, but Soo Heon is unfamiliar with this version of Jae Beom.