L.U.C.A.: The Beginning - Season 1 (2021)

Zi 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 where he undergoes tests to find out about himself. However, Zi O recalls more horrific memories while tested.

Gu Reum brings Zi O home since he has nowhere else to go or anyone to depend on. There, Zi O comes to understand just how desperate and lonely Gu Reum has been while searching for her parents.

Zi O returns to the lab where he lived as a child. An unexpected someone comes to meet Zi O and tells him a shocking truth. Meanwhile, Gu Reum finds a new lead on her search for her parents and continues her investigation.

Gu Reum and Zi O are reunited in the fiery mess of Human Tech's secret lab. Gu Reum tries to stop him, but Zi O loses control while fighting Lee Son. Zi O takes Gu Reum to the hospital, blaming himself for hurting her again.

In order to protect Gu Reum, Zi O takes her to a ranch where he used to work years ago. As the two spend their days together, Zi O enjoys the happiness of a normal person for the first time in his life.

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, Zi O asks Won Yi to meet him in a remote place.

Zi 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.

Zi 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.

Zi O dreams of creating a new world for Gu Reum and their baby, but Gu Reum wishes Zi O would come back to being more human, as he was before. Can Zi O and Gu Reum, who have chosen different paths, reunite once more?