To understand Book 4, one must grasp the rules of the series. Bahay ni Kuya is not a typical "haunted house" story. The plot revolves around a dilapidated two-story ancestral home in the province of Bulacan. Local legend says that the house is alive. It doesn't kill you immediately; instead, it "plays" with you.
If "Book 4" follows the typical structure of the series, it likely focuses on a specific pairing or a continuation of the lives of the residents. Use this guide to understand the narrative flow: bahay ni kuya book 4 by paulito work