Ena investigates Unit 5802's rapid ownership changes in the One City Complex, uncovering links to past crimes and victims. Hansaem learns about a journalist’s suicide tied to Dong-Hoon and Ena, revealing a deeper serial murder case. Suspicion arises around Yang Jongho, trusted by Hansaem but possibly hiding secrets. Ena visits a man connected to the journalist in Jeju, while she is unexpectedly arrested for murder, intensifying the mystery.