While the female lead, the second female lead, and their classmates are attending class, they receive an identical message from an unknown sender containing rules for a seven-day campus lockdown. They are soon plunged into a bizarre series of supernatural rule-based mysteries. The second female lead takes the female lead around the school to search for information that might help them escape, only to encounter classmates who have already died. As they continue searching for clues, strange rules keep arriving from the mysterious sender. As time passes, more and more people begin acting abnormally, and the resurrected dead seem to be using some method to kill others indirectly. With the dangers growing increasingly severe, will they manage to escape this terrifying ordeal?