In the beginning of the episode, we are shown how Captain Choi Jun kyung’s husband got infected by the parasyte while waiting for her outside a shopping mall. He started a bloody rampage killing almost everyone in the mall until Choi Jun kyung managed to lock him up but at the expense of her ear and her hand. The thought of this gives her sleepless nights.
Meanwhile, Su in and Kang woo decide to stick together to increase their chances of survival. They decide to tell the police what happened at the church. Kang woo calls Detective Chul min anonymously and informs him of the parasytes hideout. He in turn then lets Captain Jun Kyung know however, she gets suspicious of him when she discovers he is close to Su in.
Captain Jun Kyung gathers the grey tean forces and storms the church. However, the parasytes are gone but evidence of human remains at their store house is still there. Captain Jun kyung wonders how they were able to move so fast unaware that detective Chul min’s partner seemingly innocent Won seok is working with the parasytes for unknown reasons. He had been the one who gave them the heads up. After their investigation, they realised that one of their own was killed by their kin making the situation more dire. Then, they order Won seok to kill Jun Kyung’s husband. He’s the reason why they know their whereabouts.
Meanwhile, Jun kyung’s suspicions of Chul min grows further when she notices him putting a key holder from the scene into his pocket. Apparently, it belongs to Su in and she had lost it in church during the uproar. Chul min calls Su in to meet with her and Jun kyung decides to follow him..At their meeting in an old run down amusement park, Chul min confronts Su in asking what she was doing in the church but before she can answer him, Jun kyung appears to shoot Su in but she quickly flees with Kang woo. Soon the entire place is surrounded by the police and to increase their odds, both decide to separate. Su In’s parasyte reveals itself and tells Kang woo to find a car which they would use to escape while she takes care of Jun kyung.
They both go their separate ways. Su in manages to evade Jun kyung but she is soon cramped up by the police unable to escape. She faints and Chul min tries to protect her pleading with them not to shoot because she’s still a human being.
Meanwhile, Won seok stabs and kills Jun Kyung’s husband unaware that Kang woo saw him. When Jun she discovers her husband’s corpse, she seethes with anger. Fuming with anger, she takes the elmet which used to be worn by her husband and places it over Su In’s head, indicating she’s now her new hunting dog.
At a police conference, detective Chul min and Jun kyung argue over Su in. Chul min insists that Jun kyung is still human given that the parasite wasn’t found in her body after the tests but Jun kyung thinks otherwise. Finally, the higher ups decide that Su in will be transported to Seoul for further investigations. Chul min isn’t happy about it knowing that Su in will die if she goes there.
Therefore, he tracks down Kang woo who is about to board a bus to Gangnam and arrests him. He asks Kang woo to tell him everything he knows and ends up perplexed to find out Su in is a mutant. Kang woo also tells him that Won seok is a monster and was the one who killed the hunting dog. Although Chul min hears what he says, he doesn’t fully believe it.
He then asks Kang woo to help him free Su in but Kang woo refuses and Chul min practically roasts him alive, calling him a coward who runs away from responsibilities. His cowardice is the reason why his gang saw him as a disposable being. Chul min’s words hit hard and Kang woo finally agrees to help. They set about a plan to ensure Kang woo gets himself into the container where Su in is kept. He would then retrieve the device keeping the helmet in her head and once he has her, they would escape.
Apart from a few hitches, Kang woo manages to get himself into the container but unfortunately the team decide to go to Seoul faster than normal. Detective Choi Jun kyung personally takes the device and Kang woo disguised as an officer is forced to be in with Su in and watch over her.
But Su in is unconscious, locked in her own mind with her parasyte, Heidi as Kang woo calls her where she has to face all her demons and tragedies, from when people saw her as a monster after she had reported her Dad for assault. How her mother abandoned her and had another family. Su in even yells at Heidi for turning her into a monster but Heidi tells her that she didn’t create herself and that despite all her suffering, she still has people who loves her. Su in breaks down in tears when she sees Detective Chul min in the mirage taking care of her when she was a child.
Meanwhile, the task force finds themselves in a problem when a sudden traffic congestion takes place and they are attacked by the parasytes. This was obviously their plan in order to capture Su in. In the midst of the chaos, Kang woo grabs the device from Jun kyung but the two end up fighting until they are interrupted by a parasyte infestation. Jun kyung gets distracted while trying to save her life. Kang woo uses the opportunity and frees Su in. He and Su in drive off together while detective Chul min and Won seok go after them in their car but soon enough, Won Seok takes a detour and drives to a secluded place with Chul min who is left confused. But Su in can sense that Chul min is in danger and forces Kang woo to stop the car so she can save Chul min.
Won seok reveals to Chul min that he’s a traitor working with the parasytes to create a new world. The pastor’s parasyte arrives to attack Chul min. He shoots at it. The pastor’s body dies but the parasyte inside him emerges and cuts off Chul min’s head before invading his body.
Su in witnesses this and immediately, Heidi takes over in a rage and begins fighting with the parasyte. Woo Seok tries to shoot her but Kang woo barges in with his car and takes Su in away.
Woo seok asks how she’s doing but it’s Heidi that answers, telling him that Su in would need to rest for a long time. (Because she’s in too much pain)
