Amid suspicions that Eun Soo may have played a part in a stabbing, the team arrests its suspects. But they notice evidence of yet another accomplice.

Clues suggest Na is in danger. Later, an injured man resembling Kang Woo is spotted hobbling away from a bloody crime scene where Na's ID is found.

Cleared of suspicion, Kang Woo reveals his wretched past to Kwon Joo. Later, the true serial killer attacks Seo Yool and gives Kwon Joo an ultimatum.