The story begins with a little girl who wakes up after a traumatic attack and hears her mother calling for her. The scene shifts to a present-day teenager who abruptly wakes from a distressing daydream. She is on a bus with friends and fellow students, all excited about their road trip.

As the journey continues, the atmosphere is joyful until the bus driver unexpectedly takes a different route. Some students notice the change, but before they can react, chaos ensues. A masked individual on the bus releases gas, causing everyone to lose consciousness.