When Regina Carpenter was just ten years old, she watched in horror as her babysitter was mercilessly stabbed to death on Halloween night by a masked killer press dubbed later as Mr. Stabby. Despite the terror, Regina bravely identified the culprit, leading to his demise at Canter Bridge where his body fell over and vanished in the murky waters. Now seven years later Regina is a high school senior facing a chilling threat. Notes from an unknown sender are appearing in her locker, the same kind her babysitter received before her death all those years ago. Has Mr. Stabby returned? The countdown to Halloween night begins, and Regina must get ready to face what's coming.