A school field trip to an ancient castle goes terribly wrong for a group of friends, when a dangerous storm erupts. As they are about to leave the castle, the four friends are cornered by their arch nemesis - the class bully, who tries to pull one of his usual cruel pranks. Instead, they all get the scare of their lives, when they fall down a tunnel that transports them into the future: a future where mankind has nearly disappeared from the face of the earth, and where nature has taken control. The friends will have to face up to this hostile new world - as well as their nemesis, who must come to terms with his own trauma - if they are to work together and have any chance of making it back home...