Guillaume Bouzard is living a particularly painful chapter of his life. Called to the bedside of his dying mother, he learns a shocking family secret: his father, who has he never met, is a troll. Although initially sceptical, all the evidence eventually forces Guillaume to accept this as a fact. No, his mother isn’t mad! Now Guillaume has no choice but to try to locate this most unusual father. This is the beginning of a full-fledged quest across Brittany, accompanied by Flopi, his faithful four-footed companion.