Luo Xiaohei is a young monster who normally takes the form of a small black cat. Living freely in the forests, gradual deforestation and human development force him to flee and find a new home. Wandering the city streets, the black cat struggles to survive until he encounters Feng Xi, a fellow monster who takes Xiaohei to an isolated island inhabited by a small group of monsters. Excited to find what he thinks is his new home, Xiaohei lives with the monsters for only a short time before Wuxian, a human Guild Executor, arrives on the island in pursuit of Feng Xi.