I Cavalieri di Castelcorvo focuses on a brother and sister called Riccardo and Giulia, aged 11 and 13. They have to move to Castelcorvo to stay with their Aunt Margherita to attend school. They meet two other children, Matteo and Betta, who go on to become The Knights of Castelcorvo and face a number of challenges including magic puzzles, keys and board games, witches and places outside of time and space.