Cha Su-yeol, a police officer who has long despised his mother, the notorious 'Mantis' serial killer, must reluctantly turn to her for help when a copycat killer emerges.
Episode 1
When a series of terrible murders ensues in a residential area, Cha Su-yeol is forced to seek help from Jeong I-sin, a serial killer from the past.
Episode 2
The culprit has been arrested, but the victim’s whereabouts remain unknown. Su-yeol struggles to save a life as I-sin reveals her true intentions.
Episode 3
I-shin offers assistance with the investigation, but it's unclear why she would help a cop. Su-yeol unravels the origins of I-shin's murderous instinct.
Episode 4
The culprit begins to close in on Su-yeol's family. I-shin pressures Su-yeol to take action — but she happens to be the one threatening his family.
Episode 5
Episode 6
Episode 7
