Knock knock

Every small town has its own sinister and evil legends, but it's different for Glace County, because its legend came true. Recently, there have been several consecutive brutal murders at the town's school. A beautiful female detective begins to investigate and gradually uncovers some clues, which turn out to be related to an accident caused by a student prank many years ago. As the investigation deepens, the female detective also begins to feel the horror of the event. What exactly happened? Is it the vengeful spirit coming back? Late at night, someone is knocking on the door, but think twice before you open it, or you might be the next one...