Marc, the series' protagonist, was once a commander tasked with retrieving vital supplies like food and medicine from the dangerous surface, overrun by monstrous predators. But after losing his beloved in a scheme engineered by the fortress ruler's son — once his friend and mentor — Marc transforms into one of the very creatures he hunted.

The new season picks up where the first left off, introducing a seemingly utopian village, a stark contrast to the fortress. At first idyllic, with residents enjoying peaceful lives, the settlement is soon revealed to harbor sinister experiments and moral compromises. Marc, still clinging to his human consciousness, embarks on a new adventure to face even greater challenges.

The second season, enhanced by advanced technologies like motion capture, features over 10,000 different shots.

For producer Ruan Rui, also the founder of animation studio YHKT Entertainment, the village's design draws from ancient Chinese philosophy — particularly the belief that human perseverance can overcome even the harshest environments. While sci-fi has long thrived in the West, Ruan says he and his fellow creators have worked hard to develop sci-fi stories rooted in Chinese culture that reflect distinctly Chinese ideas.

Such instances range from characters using martial arts to fight monsters to engaging in typical Chinese pastimes like playing mahjong, eating hotpot, and gathering elderly villagers for square dancing as a form of exercise.