Security guard Zhang Biao goes missing the very night he encounters a woman in a red dress after accidentally overturning a ritual offering during his patrol. Yu Chunlan recounts the incident to Wei Qiang (the male lead), a newly hired guard, hinting at the building's eerie nature. During his first patrol, Wei Qiang overhears the same couple's conversation and, upon hearing a terrifying "murder" scream, calls the police—only to discover it was a tenant watching a drama. Yu Chunlan sternly warns him. While patrolling at midnight, Wei Qiang meets Zhang Jiani (the female lead) in a red dress, who asks for help with her suitcase. Noticing strange movements inside the suitcase and sensing her seductive advances inviting him into her room, Wei Qiang recalls Yu Chunlan's rules and refuses. After Wei Qiang sprains his ankle, security guard Lu Hao forcibly takes over his shift. While patrolling the crowded rental building, Lu Hao kicks over a ritual offering, encounters Zhang Jiani, and is lured into Room 802 before jumping to his death. Before dying, he calls Wei Qiang, warning him that the rental building is haunted. Suspicious of Zhang Jiani, Wei Qiang and Yu Chunlan investigate Room 802, discovering ritual photos that look exactly like Zhang Jiani. When Yu Chunlan knocks over an incense burner, Zhang Jiani appears but refuses to enter due to lime at the doorstep. The suitcase suddenly moves, and as Wei Qiang tries to inspect it, a conflict erupts, leaving Yu Chunlan injured. Wei Qiang and Yu Chunlan eventually subdue Zhang Jiani, only to learn she is a mentally ill patient. They burn the red dress and shoes and pay respects to the deceased.
