Shen Yue is reborn, returning to thirty minutes before she was murdered in their shared four-person apartment. She desperately tries to stop her roommates from touching the front door, but is treated as being high-strung after a nightmare. The threat of someone impersonating a delivery worker quietly approaches, and the subsequent "security guard" appears to be a rescue, but actually harbors murderous intent. Everyone faces the danger directly inside the enclosed house, uncovering a tragedy triggered by ignoring others' time and dignity. After the crisis is resolved, a mysterious note throws down a chilling ultimate foreshadowing.