Filo and Rullo, two inseparable friends, secretly set out to look for Birillo, the dog lost by Filo's father. Their friendship is strong and nothing can stop them, not even the fear of the dark or the gruff mountain man Guelfo Tabacci, who seems to be involved in the dog's disappearance. But behind this apparent reality lie unexpected events, which will force the boys to face trials much bigger than themselves.