Hao Yun, a vet at a private clinic, leads a mundane life until he accidentally discovers the world is inhabited by monsters. Worried about the secret of their existence leaking, monsters capture Hao Yun and attempt to erase his memories. When their attempts fail, Hao Yun is forced to join Monsters Bureau, where he solves cases involving monsters with the help of his new partner, Wu Aiai. As Hao Yun dives deeper into this new world, he learns that even monsters must deal with the mundane struggles of everyday life and the entanglements created by human emotion.

During a dangerous rescue mission, Commander Tiejin and his troupe are locked in heated battle when he stops dead seeing none other than the brother he lost five years before, now fighting alongside the enemy.

A Westerner finds refuge with a group of women in a church during Japan's rape of Nanking in 1937. Posing as a priest, he attempts to lead the women to safety.