Terror is an Understatement

Twenty children, who at a party, decide to have a sleepover in a locked off abandoned house several miles away. They finally arrive at the house, decked off with sleeping bags, pillows, and other sleepover essentials. But several hours later, when night comes, they decide they don't want to sleep at this house anymore, and choose to head back. To their horror, they discover that they can't leave...

One by one, they begin to die off, some with their throats hacked open into the night, bleeding rivers of blood, others suffocated to death. Some bludgeoned with lamps. The remaining are forced to have to figure this out. Which finds having to uncover who, or what, has been murdering their friends.......