A prehistoric cave boy who lives in a modern chalk pit, embodying timeless ingenuity and forming a close friendship with Barney despite their differences.

Barney’s older sister, who initially doubts the fantastical stories but gradually becomes open to the extraordinary through shared experiences.

The caring and gentle figure who represents the adult world, providing a loving environment unaware of Barney's adventures.

A group of local boys who transform from bullies to allies, expanding Barney’s social circle through their interactions with Stig.