Circle

In Part 1, Woo Jin realize that Beom Gyun is losing his memories. And at their old house, Woo Jin and Jeong Yeon finds something unexpected. In Part 2, Dong Geon tells Joon Hyeok that Woo Jin is alive. Joon Hyeok and Jeong Yeon go to a house guarded by Human B's security team and finds Professor Han there.

In Part 1, Dong Geon and Human B join hands and try to come up with a plan to get Woo Jin and Jeong Yeon. In Part 2, Jeong Yeon and Joon Hyeok go to Human B to find Woo Jin after finding out that their supercomputer won't work without Woo Jin. However, the supercomputer crashes.

Part 1: Woo Jin finds out that all the research data was destroyed. He plotted for the research data in exchange for Beom Gyun's surgery to remove the bug and gave himself up as collateral. Woo Jin finds out Dong Geon's motives. Beom Gyun's surgery goes well and Woo Jin escapes. Woo Jin gets into an accident while running away from Human B and Dong Geon. The person coming down the stairs turned out to be Woo Jin's clone. At first, Joon Hyeok denies that he's Woo Jin because of the real Woo Jin who died. But as the clone tells him his memory of the day he disappeared, he apologizes. He says he's sorry for letting him go there alone. 

Joon Hyeok suspects that Mayor Yoon has seen something that can be used against Dong Geon. Since Jeong Yeon can unlock his memories, they decide to take him out of Human B's hands and unlock it. And since Min Young is a doctor, she sneaks in to the hospital to take him out.