On a mission to clear his name, Jang Ho-jae searches for a mysterious woman. On the job, Chae-ok encounters a familiar person from decades ago.

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.

In his effort to save Chae-ok, Ho-jae makes a momentous decision. Having sustained severe injuries, they must battle through a treacherous escape.

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.

As Ho-jae's enemy threatens to hurt those closest to him, he risks everything to protect them. Will he survive the ferocious beasts and save Chae-ok?

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.