Episode Summary
Xiao Beiming's team locates a hostile, isolated female tribe while investigating the Haiya case. They earn the tribe's trust after Feng Qingzhuo saves a boy's life. It is revealed that the "monster" terrorizing the area is the tribe leader's brother, Luo Sen, who, along with other family members, became infected after visiting a mysterious city. The team successfully captures Luo Sen, uncovering a crucial link between his condition and the larger "Night Devil" conspiracy.
Spoiler Alert
The search for the truth behind the Haiya case leads Xiao Beiming and his companions into a dense, hostile forest where they encounter a reclusive, all-female tribe. An initial confrontation with a young thief from the tribe quickly escalates, with the women showing clear animosity and firing arrows at the newcomers. Realizing that in this desolate land, food is the most valuable currency, Xiao Beiming attempts a peaceful negotiation by offering provisions. While the tribe's women are starving, their deep-seated suspicion leads them to drive the group away, though they keep the much-needed food.
The fragile peace is tested when the tribe's leader, Luo Shu, grows anxious after her messenger fails to return. Fearing for her people's survival, she decides to venture out for help. A mute child from the tribe, A Xing, secretly follows her, only to be bitten by a venomous snake. Luo Shu rushes him back to the village, where Feng Qingzhuo, whose stolen medicine box was coincidentally returned by A Xing himself, manages to save the boy's life.
This act of kindness earns the group Luo Shu's gratitude. When she learns they are investigating the Haiya case, she is stunned. Still wary of Xiao Beiming, she remains guarded. To build a stronger bridge, Huo Dairong reveals her own identity as a Haiya orphan. She explains that despite being raised in the Great Qi, she and Xiao Beiming are Haiya by blood, seeking the truth about their lost families. This confession finally earns Huo Dairong the tribe leader's trust.
Luo Shu confesses she knows little, only that a "monster" brought by the Great Qi has plagued her people for years. The nature of this monster soon becomes terrifyingly clear. A sudden scream leads Xiao Beiming to a woman with a fatal bite on her neck. Feng Qingzhuo confirms the wound was inflicted by a human. A swift search by Xiao Beiming and Tong Shuang reveals a man with incredible speed and lingering blood around his mouth.
Confronted by Xiao Beiming, a devastated Luo Shu finally reveals her tribe's dark secret. She leads them to a hidden cave reeking of death, filled with the corpses of her own relatives. She explains that they all traveled to a place called Little Lonely City (Xiao Gucheng) and returned as monsters. The attacker they just encountered is her own brother, Luo Sen. He had been struggling with his condition, sometimes lucid and sometimes feral, locking himself away during his violent episodes until he finally broke free.
Feng Qingzhuo's examination of the bodies reveals the cause of death—a swollen heart—is identical to that of Old Bug, creating a direct link to the mysterious "Night Devil" (Ye Sha). To capture the dangerously unstable Luo Sen, Xiao Beiming devises a trap, luring him with drugged food. The substance makes Luo Sen dizzy but also triggers a violent frenzy. Ultimately, it is a physical trap that allows the group to successfully apprehend him, bringing them one step closer to the horrifying truth of what happened at Haiya.
