Thorgal's son, Jolan, has grown up to be a strong and inquisitive child while the three of them live on a deserted island. His parents are puzzled by the strange symbols he keeps drawing of which he can't tell their meaning. In his mind find friendship with a boy of his age that seems to come out of the nowhere. The child seems to be lost and afraid of adults. Also because he is a mute he isn't able to answer any questions regarding his mysterious and sudden presence.