When a mother leaves her two children at their grandparents' house for vacation, things start out great until bedtime. There are no rules during their stay except the children are instructed not to come out of their rooms after 9:30 PM but after sneaking out after bedtime they realize something is very wrong with grandma and grandpa. As the days pass the strange behavior continues with the grandparents and the children must try to convince their mother to come back for them. Until their mother comes back, the children must survive their stay with their grandparents.