While looking for the same person, Ho-jae ends up saving Chae-ok, who's being chased by a mysterious being. Ho-jae begins to wonder more about his past.
Chae-ok agrees to work with Ho-jae to find Seung-jo, but they soon find themselves in peril. Meanwhile, Chae-ok's monstrous instincts begin to surface.
Ho-jae tries to piece together everything that has been hidden from him. Chae-ok discovers that the atrocities of the past continue to the present day.
After a test subject wreaks havoc in public, Jeonseung Biotech goes into damage control. Fate drives Ho-jae and Chae-ok to confront the company head-on.