Ji O wakes up from losing his consciousness and has no clue where he is. In fact, he isn’t sure who he is either. He just knows that he has a body covered in wounds and there are fallen people all around him. One man walks up to him with a knife in his hands. A year goes by and Gu Reum, a police officer, finds out that the man she was searching for is dead.

Ji O gets admitted to the ICU after suffering extensive injuries from the fall. Gu Reum also ends up in the hospital where she suddenly remembers seeing Ji O during her childhood. Feeling confused, she starts to look into Ji O’s identity. Meanwhile, the researchers from the Human Tech lab continue trying to bring Ji O in.

Ji O takes Gu Reum somewhere safe to heal her injuries. Gu Reum asks Ji O questions about her parents, but he doesn’t remember anything about them. Gu Reum takes him to a church to help him regain his memories. Meanwhile, Chul Soo scolds Son for losing Ji O. Son makes desperate efforts to find Ji O and Gu Reum.

Ji O remembers that he burned down the orphanage as a child and is in a state of shock. Gu Reum takes him to Jong Hwan at the NFS where he undergoes a number of tests to find out about himself. However, Ji O recalls more horrific memories while being poked and prodded. He runs away and ends up going to see an old friend.

Gu Reum brings Ji O home since he has nowhere else to go or anyone to depend on. There, Ji O comes to understand just how desperate and lonely Gu Reum has been while searching for her parents. Meanwhile, Lee Son is furious that he let Ji O go yet again. He decides to take a big risk in order to capture Ji O once and for all.

Ji O returns to the lab where he lived as a child. An unexpected someone comes to meet Ji O and tells him a shocking truth. Meanwhile, Gu Reum finds a new lead on her search for her parents and continues her investigation. When she follows the lead, she winds up at a place she once visited before.

Gu Reum and Ji O are reunited in the fiery mess of Human Tech’s secret lab. Gu Reum tries to stop him, but Ji O loses control while fighting Lee Son. Ji O takes Gu Reum to the hospital, blaming himself for hurting her again. Meanwhile, a rift begins to appear between the members of the L.U.C.A. Project.

In order to protect Gu Reum, Ji O takes her to a ranch where he used to work years ago. As the two spend their days together, Ji O enjoys the happiness of a normal person for the first time in his life. However, Gu Reum wants to return to her old life instead of living as a fugitive forever. Meanwhile, the L.U.C.A. project proceeds with implanting the embryos into the surrogates.

Captain Choi shows up at the place where Gu Reum and her baby are being held captive. He tells Gu Reum something she finds hard to believe and doesn’t know what to think. Meanwhile, Ji O asks Won Yi to meet him in a remote place. The two of them plan to tail Captain Choi to find Gu Reum.

Ji O falls into despair when his only friend, Won Yi, faces danger because of him. He becomes more desperate to find Gu Reum and their baby and makes riskier moves. Meanwhile, a group of men raids the hotel where Gu Reum was being held captive. After she is dragged off to another place, Gu Reum must fight against her captors to protect her child.

Ji O feels a sense of emptiness as the cult followers cheer for him, believing that he is an angel from above. He then decides to cross the line, for Gu Reum and their child’s sake. Gu Reum tries to stop him, and they keep disagreeing. Meanwhile, Kim Chul Soo, feeling backed into a corner, plans his final attack.

Ji O dreams of creating a new world for Gu Reum and their baby, but Gu Reum wishes Ji O would come back to being more human, as he was before. Meanwhile, Gu Reum decides to pursue Kim Chul Soo, but she still faces danger at every turn. Can Ji O and Gu Reum, who have chosen different paths, reunite once more?